is the rasengan better than the chidori ?

[super yang]

rasengan is the canonically superior ninjutsu, yes

if all things are equal, it will beat rasengan in a clash

 

[PT1990]

Let me answer your question with another question. Did Obito die when Kakashi hit him with a Raikiri?

No, but he was very badly hurt. He was in far worse shape than when Minato hit him with Rasengan.