Would be interesting to see how TTL would envision a World Without Nazism since that concept is distant even to us and very different from one where the nazis simply lost like
Grasshopper Lies Heavy
Bit depends POD but taking how anti-Germans people are and the world is probably more cynic due much longer and more traumatic WW2, I don't think them expecting that being too much better.
The problem is this: the Nazi order TTL not only lasted much longer, but the damage it inflicted on society is more obvious and visceral.
In the same way that OTL Americans have their view on Islam defined by ruin in Manhattan, TTL Americans' view of Germans isn't Volkswagons or Rammstein but the ruins of Paris, the empty fields of Eastern Europe where once great cities flourished, the attack on New York, the millions of refugees fleeing horror unimaginable cruelty, and millions of traumatized soldiers pushed to their limit on several occasions.
It doesn't help that these monsters happily broadcasted their destruction.
Let's throw in that Imperial Germany also did terrible things in WW1 and Africa, and simply put, Germany has a lot of historical baggage that will take centuries to overcome.
Personally I wouldn't class the Nazis as ultranationalists: rather I think of them as fundamentalist Social Darwinists. The Nero Order shows that at the end of the day they didn't really give a shit about even German life.
We could even parody the Muslim Kalimah to describe Nazism as "there is no god but Race War, and Hitler is his prophet".
I think there is a good element of Social Darwinism in the TTL Nazi's actions. The whole ideology was "we either must slaughter the undesirables or our children will become effeminate homosexuals."
But when I say ultranationalism, I'd say "a cult-like obedience to the state." Millions of Germans cared only for their loyalty to the Fuhrer, and in that loyalty, they committed tremendous barbarity because their loyalty to their regime mattered more than any other social value. And while some German officers through in the towel, it was only to protect Germans. They didn't particularly care when the Jews were practically wiped out and when Paris was destroyed.
All that mattered to the Germans was "the Fatherland." The evil of Hitler's cabal is not surprising, but the willingness of millions of Germans to hurt and kill countless people is the true horror.