>> But being an "anti-Christian nihilist," (which I think is an ahistoric view of Nazi religious philosophy) does not establish that such a person is an atheist. One, for example, could be an anti-Christian nihilist and yet believe in any number of religions and deities. <<
By definition, a nihilist does not believe in the god of any religion. If I can drive a distinction between atheism and nihilism, it would be that an atheist believes that there are zero gods, and a nihilist does not believe in the concept of a God. Some nihilist might consider that atheism has made a god out of science and reason.
>> Parts of it were occultish and pagan (although not a seriously large part), many (as in any society) were agnostic, atheists, or non-practicing, but the vast majority of party members at the time continued to practice their religion without the type of political disapproval one would expect had the party been atheistic. <<
A lie created by the left-wing, God-hating media. As I just related in another comment, the Boston Globe had, on the same day, on the same physical sheet of paper, a front-page, above-the-fold headline that the Pope had never condemned Nazism, and a back-page retrospective look at the 1939 Boston Globe, featuring an image a papal condemnation of Nazism, scrawled across the top of the the 1939 paper.
The Nazis went out of there way to create images showing acceptance by church authities, such as the infamous photo of German bishops marching in a Nazi parade. The Nazis, of course, downplayed the rejection of such appointments by Rome; the harsh, universal criticisms; the thousands of Catholic martyrs. In essence, the media now accepts this false Nazi propaganda. Which Nazi leaders were communicants, of Lutheranism or of Catholicism?