You'd be wrong. The Nazis are all over Ukraine, as they are (unfortunately) good fighters willing to fight and die.

That being said, they had a high concentration in/near the Donbas and particularly in Mariupol, where roughly 2000 soldiers (unknown how many from Azov) just surrendered.

Russia is close to encircling an estimated 15,000 more soldiers in/near Lysychansk. The Donbas is where the best and most Ukrainian troops are, and securing the Donbas was the highest priority for Russia, not de-Nazification.

The Nazis in Ukraine threaten and kill mayors, judges, police, even Zelenskyy openly. They don't need a political title when they can do what they want already.