Is There a No Fly Zone?

I initially decided to to weigh in on Ukraine because so many other people were. But as the situation becomes more and more potentially apocalyptic it started to appear that I would have to. But don't worry, I don't rehash the same talking points as everyone else. My big worry is whether we can figure out some point of stability where nukes exist, but no one uses them. We had that during the Cold War, but that was a bipolar situation where both sides were very similar in strength. Essentially the easiest situation imaginable from a game theory perspective. Unfortunately the future promises to be multipolar, contain lots of nations with nukes who all are at various power levels. How are we going to navigate this treacherous situation? Is it even possible?