On the one hand he's smart enough to know that the outcome would not help him.at the end of WW2 Hitler committed suicide rather than face the consequences of his action. Hitler didn't have nukes.
On the other hand, his fragile ego might see it as preferable to being beaten.
I can imagine that China would start pushing hard if Putin started pushing nukes.
when Putin feels like defeat is near he'll choose suicide as well,.. but choose to take the hole world with him.
china won't have time to do shame. once the first nuke is launched it will be nuclear winter in a matter of minutes. Russian isn't going to launch a "warning" nuke. when they launch he'll launch all 1500 nukes at once.