Seems to me atheism gives no ethical guidance at all--excepting that implicit with the implication that ethical principles are a bi-product of our biology and an ethical proposition is not something that can be objectively true or false (I maintain that some ethical propositions are true and some false, but then I am not an atheist).
Nazism, while very anti-Christian, was not Atheistic/materialistic. It was kind of a racist ancestor force pantheistic cult.
A satanist is by definition not an atheist.