Russia also said demilitarisation and pointed fingers at NATO. If it's this and denazification, it would suggest that Russia was hoping for NATO/the West to get involved in exactly the way that it got involved.

Further, the Russian perspective is that NATO was already involved by running a coup then supporting about a decade of shelling in Donbass. If that's the case – and the important detail here is not what westerners think NATO reps were doing in Ukraine all those years, but what Russia thought – there is no logical scenario in which Western involvement comes as a surprise. It was known to be there before the invasion.

And if NATO really wasn't in Ukraine before that invasion, the point still stands: Russia expected NATO involvement even if it's initial intelligence was faulty.

That doesn't mean denazification is the main reason for the invasion. Although there are people who accept that reasoning as it was more than just a Nazi presence. It was an organised Nazi terror campaign against ethnic Russians living in Ukraine, killing thousands.