Hell Stab is definitely stronger when done by the same person. You can't compare EoS Sasuke's chidori power level to 3rd Raikage's power level. If Sasuke at peak power did both attacks which would be stronger is how you need to pose the question and the answer to that is Hell Stab.
I don't agree with hell stab> chidori
Chidori even without the meteor busting feat wrecks.
You forget he can mix enton with it
His susano can use chidori which is even more powerful than the handheld version.
Also he bisected Godara with it or was that with a sword if its the former then that feat alone shits on hell stab hype.
Take into account hell stab feats aren't that great the best feat it has is injuring the raikage himself but even then the feat is only great because of his hyped durability that no shinobi that has faced him can back up those claims.
Chidori has more feats and better feats.