In Summary:
1-Fascism is a term that was originally referred to the fascists of Italy under Mussolini. Nazism on the other hand, referred as National Socialism, is in an ideological concept of the Nazi Party.
2.For Fascists, the state was the most important element. But Nazism emphasised on racism.
3.While fascism considered state as important, Nazism considered ‘Aryanism’ as more important.