1.Hitler never had NATO to go up against.
He had two great powers arguing that the invasion of Poland would result in war. Which it did.
There's plenty of non-NATO states that Russia could invade. Finland, Belarus, Moldova (the parts it hasn't occupied), Ukraine (the parts it hasn't occupied), Georgia (the parts it hasn't occupied), Azerbaijan, Kazakhstan, Mongolia, etc...
2.If England and France had nuclear weapons, there's no reason to believe Hitler would have done anything.
Well, Hitler picked a war on several fronts, in one case stabbing an ally in the back (USSR), and ended up creating a war on the largest empire on earth (British) and the largest economy on earth.
So I wouldn't be so quick to assume he wouldn't continue to be stupid.
3.Germany's military was much stronger than Russia's is today.
And what do you base this on? If you look at the numbers, assuming Hitler thought he'd have to fight everyone, Germany's population of fighting-age men looked pretty pathetic compared to the forces that could be brought against him.
If you assume Hitler thought he'd get away with partitioning Poland just like he got away with the Sudetenland and the annexation of Austria, then it doesn't matter.
Now, Hitler is dead and gone. The question is what does Putin think, and how much can Putin control the nationalism he's unleashing? Does Putin assume if the annexation of the Crimea goes well, he can make the same type of play again? So far, Russia's aggressions (Chechnya, Georgia, Ukraine) have gone very well for distracting the Russian population.
My fear is, similar to the events before WWII, is that Putin is going to take one action too many, and will end up starting a major war. He actions, while arguably (very much so) beneficial to him in the short term, are more or less guaranteed to cause other countries to turn against him. It's quite frankly obvious to anyone with half a brain and a knowledge of history to realize that the Baltic states and Poland were going to go batsh-t crazy over this. With neighboring countries turning against Russia, it's going to be easy for him to play up more nationalistic fervor. That is unlikely to end well.