There are some surface similarities, but that’s about it, between the anti-Japanese feeling in the US after Pearl Harbor, and the systematic racist ideology of the NSDAP. Official US policy towards Japan never endorsed any of the admittedly widely tolerated and perhaps even widely felt racially motivated hatred of the Japanese. Individuals, certainly, quite a few of them, as has been well documented, but not the government as a whole. The Nazi worldview was just that, though; an officially sanctioned, fully endorsed and in fact mandated ideology of racial superiority.
I mean, within a few years of Hiroshima and Nagasaki, we were working hard to help the Japanese rebuild, and forging some pretty strong economic, military, and cultural ties. And even at the worst of the Pacific fighting, Americans never denied that the Japanese were tough SOBs. The Marines may have hated “the Nips,” but they sure respected their ability to fight for all those islands.
Much of the propaganda was a variation on the usual demonization of the enemy you see in all wars. But look at the posters and ads and stuff. The Japanese are often sneaky, and aggressive, and yes they are portrayed in what would now be considered highly offensive racial stereotypes. But compare this stuff to the anti-Jewish, anti-Slav propaganda the Germans put out. There, the entire race or ethnic group is targeted, and assigned horrific and denigrating characteristics far beyond buck teeth and thick glasses. And the US propaganda didn’t highlight women, children, civilians, and Japanese culture, but focused pretty much exclusively on the image of Japanese soldiers, sailors, or airmen–military personnel.
There’s a huge difference I think between generic middle of the century racism–the US had a long history by that time of anti-Asian feelings, going back at least to the Chinese Exclusion Act, and really, most Americans didn’t separate one Asian form another with any regularity or clarity–and what the Nazis did.