Europe got incinerated, the USSR suffered because it either sided with the U.S. against China or didn't acquiesce to the Chinese if they tried to annex it like the U.S. did with Canada in the Resource Wars.
Incinerate or not, America was incinerated and they still had bunkers and vaults to protect people.
Also, I do not believe that China would be so stupid as to try and take over Russia. Napoleon and Hitler both failed their own massive attempts to do such a thing, I doubt the Chinese would be so stupid they tend to pick up history books.
A land war in Russia never goes down well for the invaders.