To be more thorough:
IF Chiyo was stronger than Rasa, why wasn't she made Kazekage, the Shadow of Wind?
First, allow me to present why i think she may be stronger than Rasa.
The Sannin were known as the strongest in the world, stronger even than Kage. The reason for the Sannin being respected started with them surviving against Hanzo, who then recognised their power and named them thusly. Chiyo herself matched this when we are told she clashed several times with him. Hanzo himself solidifies this achievement when he says to Mifune: "then why are you still alive?", so as to say that anyone who clashes with him suffers certain death.
Secondly, Chiyo was a rival to Tsunade in the war days. Now their rivalry is based on Tsunade finding a way to make antidotes for the poisons of Chiyo. That poisoning and antidotes are their specialties suggests that in a straight fight, Chiyo is stronger.
Since the Sannin were known as above kage level, this puts Chiyo in the same breath. That Orochimaru killed Rasa solidifies this. Even as Rasa is shown alongside the strongest kage in history, no one claims them above the Sannin so that limit stands.
Another important point is that Choza Akimichi, a veteran, claims Tsunade being a part of the Five Kage guarantees victory againsr Madara. Of course he is quickly refuted by her ex boyfriend, but this speaks to what is expected of her. Not simply her, but compared to four other Kage and at her current age. Her current age there is not only an old lady who specialises in close quarters combat (so physically weaker than her prime), but specifically one who has been idling in bed for days and before that had been basically a clerk for many years. So considering those factors, a prime Tsunade would be much stronger in straight combat. So if Chiyo compares to and even beats a prime Tsunade, she is then implied much stronger than the other kage.
So by comparison, Chiyo is along side the Sannin as being superior in combat to Kage.
Then we go by her showings, which back this up.
She fought and used impressive powers against Sasori. Sasori is an Akatsuki (generally above Beast Host level, which itself is above Kage level). Before that, he somehow managed to defeat the 3rd Kazekage, who himself is implied to be closer to Hanzo than normal Kage. This is with the Sand Village considering it impossible to "so easily" defeat him (such that there was no sign left of his existence or the fight). In a world with talents like Minato, Hiruzen, the Sannin and kage like the 3rd Raikage, 2nd Tsuchikage and 2nd Mizukage, that basically says that even those guys would struggle to no end with him. And of course, the man is directly put above Rasa with his Iron Sand being considered tye most fearsome weapon instead of the Gold Sand used by Rasa. So for Sasori to have done that puts him at a very high level even before he got his other powers. Of course, he then went on to add his 296 puppets and years of experience to the mix. So for Chiyo to even make a blimp of a difference against suchca fellow puts her above the level of kage. That she did so only aided by an inexpreinced 16yr old and with a near complete lack of knowledge on Sasori is even more hype for her. So she did amazing stuff against Sasori.
After that, we see her reanimated and controlled by Kabuto. This is a Kabuto whose lack of knowledge about fighters is noted to hold back their (his) output. Nonetheless, she is also summoned without her puppets, which is reasonably 90% of the power of a puppet master, if a ninjutsu wielding swordman loses 50% of power without their main weapon. Among these powers we have the Mother and Father pupoets which move with speed to slice through wooden constructs like nothing. We also have the Chikamatsu Ten with hax like chakra blades, movement seals and chakra seals, on top of being another ten immortal bodies that she can toss at opponents with speed.
So Chiyo is not only summoned weaker, but without her main power.
Still, she manages her way against a clone of KCM Naruto, whose speed powers are noteworthy against characters like the 3rd Raikage who live off of speed.
So this is Chiyo, someone noted alongside the Sannin and even Hanzo as a legendary combatant.
Now if you look at the first line, this was clearly meant as a setup (to be honest, i don't think i even needed it for my main point, but i figured for the fun of it) for a different thread. However, i figure the topic of her power level is worth discussing itself. I would also like to avoid derailing the main thread with a questioning of this its premise and i know from experience some would question it.
So I'm gonna leave this here for its own discussion. How powerful is Chiyo in your view?
IF Chiyo was stronger than Rasa, why wasn't she made Kazekage, the Shadow of Wind?
First, allow me to present why i think she may be stronger than Rasa.
The Sannin were known as the strongest in the world, stronger even than Kage. The reason for the Sannin being respected started with them surviving against Hanzo, who then recognised their power and named them thusly. Chiyo herself matched this when we are told she clashed several times with him. Hanzo himself solidifies this achievement when he says to Mifune: "then why are you still alive?", so as to say that anyone who clashes with him suffers certain death.
Secondly, Chiyo was a rival to Tsunade in the war days. Now their rivalry is based on Tsunade finding a way to make antidotes for the poisons of Chiyo. That poisoning and antidotes are their specialties suggests that in a straight fight, Chiyo is stronger.
Since the Sannin were known as above kage level, this puts Chiyo in the same breath. That Orochimaru killed Rasa solidifies this. Even as Rasa is shown alongside the strongest kage in history, no one claims them above the Sannin so that limit stands.
Another important point is that Choza Akimichi, a veteran, claims Tsunade being a part of the Five Kage guarantees victory againsr Madara. Of course he is quickly refuted by her ex boyfriend, but this speaks to what is expected of her. Not simply her, but compared to four other Kage and at her current age. Her current age there is not only an old lady who specialises in close quarters combat (so physically weaker than her prime), but specifically one who has been idling in bed for days and before that had been basically a clerk for many years. So considering those factors, a prime Tsunade would be much stronger in straight combat. So if Chiyo compares to and even beats a prime Tsunade, she is then implied much stronger than the other kage.
So by comparison, Chiyo is along side the Sannin as being superior in combat to Kage.
Then we go by her showings, which back this up.
She fought and used impressive powers against Sasori. Sasori is an Akatsuki (generally above Beast Host level, which itself is above Kage level). Before that, he somehow managed to defeat the 3rd Kazekage, who himself is implied to be closer to Hanzo than normal Kage. This is with the Sand Village considering it impossible to "so easily" defeat him (such that there was no sign left of his existence or the fight). In a world with talents like Minato, Hiruzen, the Sannin and kage like the 3rd Raikage, 2nd Tsuchikage and 2nd Mizukage, that basically says that even those guys would struggle to no end with him. And of course, the man is directly put above Rasa with his Iron Sand being considered tye most fearsome weapon instead of the Gold Sand used by Rasa. So for Sasori to have done that puts him at a very high level even before he got his other powers. Of course, he then went on to add his 296 puppets and years of experience to the mix. So for Chiyo to even make a blimp of a difference against suchca fellow puts her above the level of kage. That she did so only aided by an inexpreinced 16yr old and with a near complete lack of knowledge on Sasori is even more hype for her. So she did amazing stuff against Sasori.
After that, we see her reanimated and controlled by Kabuto. This is a Kabuto whose lack of knowledge about fighters is noted to hold back their (his) output. Nonetheless, she is also summoned without her puppets, which is reasonably 90% of the power of a puppet master, if a ninjutsu wielding swordman loses 50% of power without their main weapon. Among these powers we have the Mother and Father pupoets which move with speed to slice through wooden constructs like nothing. We also have the Chikamatsu Ten with hax like chakra blades, movement seals and chakra seals, on top of being another ten immortal bodies that she can toss at opponents with speed.
So Chiyo is not only summoned weaker, but without her main power.
Still, she manages her way against a clone of KCM Naruto, whose speed powers are noteworthy against characters like the 3rd Raikage who live off of speed.
So this is Chiyo, someone noted alongside the Sannin and even Hanzo as a legendary combatant.
Now if you look at the first line, this was clearly meant as a setup (to be honest, i don't think i even needed it for my main point, but i figured for the fun of it) for a different thread. However, i figure the topic of her power level is worth discussing itself. I would also like to avoid derailing the main thread with a questioning of this its premise and i know from experience some would question it.
So I'm gonna leave this here for its own discussion. How powerful is Chiyo in your view?
Hanzo / SPoP = Sannin / Akatsuki / CHIYO / Beast Hosts = Tailed Beasts / Legendary Kage / Kage / Clan Specialists / Legendary Jonin . . . roughly speaking.