Putin should be extremely grateful that NATO isn't nuking his ass. Not for Ukraine, but for threatening to use nukes. In the Great Game that is considered to be "not acceptable". Even if we go back to RealPolitik, it's a balance of power, not a terrorist game.

On a more 1980's note: If this is a nuclear terrorist scenario then now would be the time to strike. Russia's nukes are probably in worse shape than their tanks, why wait till they fix the stuff?

Yeah, the above is very bad. But we're back to 1982 thinking here, and that's probably the best response in that type of game. Putin lighting his stuff off first is not going to work well: ABM systems are a lot better than the late 1980's tech and I'd guess that a lot of the stuff wouldn't launch anyway. The response to such a move would be could best be termed an "out of court settlement" turning the leadership into glowing glass, trashing what's left of their launch capability, and sparing most of the people.

Where you go from there is complicated. Nation building is not the forte of the US and there will be 140 million very unhappy people with broken Iphones......