Idiocy. No country with nuclear weapons is going to allow itself to be invaded and large chunks of its territory seized by invaders.
China won’t invade Russia like Russia did to Ukraine. Instead, the Chinese will wait for (or foment) a civil war in Russia, then come in on the side controlling the nuclear weapons. Then it will be next to impossible to get the Chinese out.
Which is why the globalist types and especially Obama and the Russians wanted Ukraine to give up the nuclear weapons it had. So long as it had them it would have been safe from invasion.