Mr. Poutine claimed that Nazis were operating in Eastern Ukraine, which gave him an excuse to invade.
Mr. Poutine also has slim historical evidence to back his claim. Many centuries before Mr. Hitler invented Nazisim, Jews were employed by the Russian Tzar to collect taxes in Russia, Ukraine, Poland, etc. This practice made theses Jewish tax-farmers unpopular symbols of the oppressive Tzar, so poor peasants reacted with pogroms (riots, stampeding, arson, lynching, etc.) for many centuries. Pogroms against any Jews were a recurring theme in Eastern Europe.
Then during World War 2, some Ukrainians aligned themselves with the invading Germans and helped ship a few thousand Ukrainian Jews to concentration camps.
Circa 2014, the Ukrainian Azov Battalion resisted the Russian invasion of Eastern Ukraine. Some Azov Battalion members were severely right-wing, bordering on fascist or Nazi. They even held torch-light parades and waved their version of runes. Please remember that the runic alphabet was the founding alphabet of Kievian-Russ, a good 1,000 years before Hitler.
Yes, some Azov Battalion members counted Jew-bashing as a popular sport, but that element was suppressed when the Azov Battalion was integrated into the regular Ukraine defense forces. The most ardent right-wing Azov leaders drifted into politics.
Please keep in mind that Mr. Poutine's distorted definition of "Nazi" no longer meshes with Mr. Hitler's definition of Nazism. Instead, Mr. Poutine includes anyone who opposes him.
So, yes, there is slim evidence of Nazism in Ukraine (circa 2104), but you really need to drink Mr. Poutine's brand of Kool-Aid to understand his attitude.