Russia is not going to use nukes.
We are not going to blow up the world to save Ukraine and Russia/Putin knows this. If he decides to use nukes what are we going to do? What can we do?
No one want it, Putin and especially China. Current atomic weapon are no more the little Nagasaki Firecrackers.
They are not going to risk their security for Ukraine. They wouldn't risk starting a nuclear war over Ukraine, it's stupid, even for their standards