Most all countries have Neo-Nazis, at least in Europe. It's arguable that Russia might have the most.
A mob didn't take over Kiev. A mob didn't install Neo-Nazis in key posts.
Six key cabinet positions are held by the Swoboda party, which is openly neo-Nazi. Here’s an article after the first two posts were filled:
Here’s another source with an update as the number reached six:
http://peoplesworld.org/ukrainian-ultra-rightists-given-major-cabinet-posts-in-government/