In my opinion it depends on what you mean by Nazi.
The first definition that comes to my mind is someone who actually admires Hitler for what he did to the people he had killed. These people would be evil to the core and would rightly be called Nazis.
The second definition that comes to mind is someone who wants to wipe out or destroy entire groups of people that they either don't agree with or which don't fit their mold of perfection. Radical Muslims for example, want everyone to be Muslim or dead, so I think it's fair to place the Nazi label on them.