Ehhh it’s a bit of a tough call.
Chainsaw man’s ability is just total conceptual erasure and it comes from him devouring his enemies.
In canon he’s erased: Nazis, world war 2, the human sixth sense, aids, the light of a freaking star, nuclear weapons, and like organized religion.
All those things simply don’t exist anymore, from past, present, and future and completely erased from everyone’s memories.
So it seems like CSM’s conceptual erasure is on a higher level than what Aizen has dealt with so if he were to somehow eat him. Aizen would probably actually die.