Russia's existence is not at stake. If the US was talking about toppling Moscow, then OK, maybe Putin would really consider putting nukes into play.
No non-mental leader is going to enter an all out nuclear war over capturing a nation merely to increase their "land padding" against NATO. This is how I know he's bluffing. It's obvious to me.
So Russia always gets their way because they'll simply say, "I'll nuke ya!" And the world's super power will fold every time?
I guess China will be using that bluff next?
Another often overlooked point, imo, is that the closer a leader brings a nation to all out nuclear war, the more likely the military brass will stop them. While the leader might be suicidal/mental/etc., that doesn't mean the brass is also. There is a good reason Putin is super paranoid now, and isolating himself.
If we are going to fold every time Putin says, "boo!" Fine.
But if we are ever going to grow some balls one day--and not fold to that threat; then this is the day! This is a low risk scenario in which to show the world that we are a super power in fact, and not just because of the size of our military machine.