Originally Posted by Yachtzee
What past? They certainly weren't trying to bring back the Kaiser and nobility that held power pre-WWI and not the decentralized Holy Roman Empire before that. Maybe you mean the one they manufactured from whole cloth from bits of German mythology and pseudoscience to justify their eugenics and anti-Semitic policies. In fact, the relationship between conservatives and the Nazis was always difficult and it was conservatives from the aristocracy and clergy that made up much of the group involved in the July 20th plot to assassinate Hitler. That's not to imply that the conservatives were always anti-Nazi. However, their relationship was always more tolerance than affinity.
Nationalist movements come in all kinds of flavors that don't necessarily fit into the left-right spectrum. An example of this would be to compare the Nazi party with the Freiheitliche Partei Österreichs of more recent history. Whereas the Nazis combined nationalism with socially-oriented welfare and economic policies, the FPÖ combine their nationalism with liberal economic policies (less government, lower taxes, the free market, individualism). The Nazis also were anti-democratic, whereas the FPÖ works within the democratic system and oppose imposition of a totalitarian regime. In many respects, the FPÖ bears little resemblance to the Nazis, yet it gets lumped in with them as a far right party because of its anti-immigrant stance.
Nobody is equating Nazism with conservatism, merely that Nazism is by definition a ultra-right wing ideology and is considered as such by pretty much every reputable source that I've ever seen. The fact that the vast majority of conservatives in Nazi Germany disagreed with the policies of the Nazi state isn't surprising, the Nazis were far, far to the right of these groups so it's no surprise that there was friction. The fact that such friction existed doesn't mean that Nazism wasn't an ultra-conservative ideology.
This isn't a political opinion, it's an almost universally recognized fact.