Having grown up in some rather terrible places and having the displeasure of close proximity of American Nazi types I'd have to say that in the US there are very few German style true believer Nazi's. The modern ones have a mixed system of odd Christian and Nazi views mixed together, with a strong emphasis on racism/racial purity/and gods chosen people.

https://www.splcenter.org/resources/extremist-files/christia...

>Christian Identity (CID) is an antisemitic, racist theology that gained a foothold during the Civil Rights Era and reached a prominent position within the racist right by the 1980s. “Christian” in name only, CID doctrine claims that white people, not Jewish individuals, are the true Israelites favored by God in the Bible. The movement has maintained a contentious relationship with evangelicals and fundamentalists, who believe that the return of Jewish people to Israel is essential for fulfilling end-time prophecy.

>>While the CID movement may be small, its rhetoric has seeped into more mainstream Christian nationalist ideologies, such as Dominionism.

Actual CID churches are few and far between themselves their ideas are very common in online forums and quickly adopt memes and theories that mirror their views. 'Replacement theory' is one of these that's common in more mainstream America.