Why Russia will lose this war?

Now the question is, what's Putin's next move? He doesn't know how to wage war, but as a former KGB guy, he certainly knows how to watch his back. It's quite unlikely he's going to be deposed.

But if he's not being deposed, and he's cornered, what's he going to do? My bet is that one way or another, he's going to use nukes. He has the choice to use them in such a way so people don't die (e.g. drop a nuke in Siberia somewhere, just to show your nukes still work). But considering that today there was a "referendum" in Belarus to allow nukes on their country, there's a chance he plans to outright use nukes in Ukraine. I really hope not a lot of people will die.