Try "Hitler's Millennial Reich" by David Redles. I wrote a paper on this topic back when I was an undergrad, but I can't seem to find it at the moment. That's the one source I remember right now.

The short answer is that several Nazis were interested in various forms of the occult, Himmler probably foremost among them. There was always something of a religious tension in Naziism, because the origins of Christianity (and Jesus himself) were so closely linked to Judaism. Himmler and others were drawn to Germanic paganism and the occult, a la Helena Blavatsky. But the Nazis knew it would be impossible to turn a deeply Christian population away from its traditional beliefs, so instead they publicly allied with the mainstream churches (see the Reichskonkordat for Catholic relations and the Deutsche Christans for Lutheran relations) and supported historical and archaeological research claiming that Jesus was not ethnically Jewish. Overt occult tendencies were mostly reserved for true Nazi believers, like members of the SS.

You might be interested also in some of the previous answers in our Nazis and the occult section of the FAQ, especially the one by u/commiespaceinvader.