Are there Nazis in Ukraine? Yes Is that number substantial? Meh, probably not outside of a few groups. Did Russia care before 4 months ago? Not really
At this point, Russia basically just uses Nazis as a catch all term for people who are “unfriendly” to Russia.
Meanwhile, it was the Soviet Union who made a pact with Nazi Germany. Not the rest of western Europe. Not the US. Not the rest of Eastern Europe.
Shhhh... facts are not important. Just because they divided up Poland with Germany in 1939 doesn't matter. But, the rest of Europe DID give them all of Czechoslovakia with a "Please don't invade us..." plea.
Stalin's faith in Hitler will always be a mystery. For a guy who didn't trust anyone, he couldn't fathom that Hitler would do him wrong.
For better or worse, Russia has always been closer to some level of medieval serfdom than a "modern" nation. I don't know what the correct answer would have been after WW2, they very well may have voted themselves into the same situation they had before, based on familiarity.
Basically this is their last option. European countries didn’t give them shit in July monetary wise and Americans are funding the whole war effort now. We’ve about exhausted our weapon systems to give them that don’t take in-depth training to operate, and the ground is about to be frozen in the winter allowing Russian tanks and equipment more freedom to move around the country and harder to ambush.