"So the Nazis were what? Atheists?"
Despite your tagline, I smell a troll.
Hitler (like Rosenberg) believed that he had found the secret key to history--which is what Marx had also claimed.
But Hitler thought Marx was wrong. That instead of class struggle, the struggle was between peoples.
(And yes, Hitler was an adamant believer in evolution. Much of his theories is based on Darwinism as he understood it.)
Hitler believed that Christianity had been used by the Jews to infect and degrade the Aryan race. That it is why he saw it as the worst calamity to hit mankind in history.
He and his cronies wanted to wean the German people away from Christianity and into "positive Christianity" -- which in truth had nothing to do with Christianity whatsoever.
What it was was a mixture of Germanic folklore and pre-Christian paganism. It was meant to develop loyalty to the race/the people/the blood/the volk and to build up the warrior mentality.
That's one reason why Hitler admired the Moslems so. He felt they were very warlike and very militant about advancing their blood/people.