Atheists and Totalitarians
You can't simply compare Nazis and Communists here.
The Nazis sort-of accepted the existing state religion, and there still is a lot of concern about the relationship of the church, the state, and the Nazi party. In general, the Nazis co-opted and subverted religion to support their "infrastructure" and plans.
The communists opposed religion as a supersition. Many parts of their activity were anti-religious, sometimes to excess. Nonetheless, their systems share may attributes with those of established religion, as a method for controlling "primitive" people...