a couple of Chinese citizens I’ve spoken to nowadays report that US racism has crept in among the nationalists (racial stereotyping about wealth and criminality which I’d rather not repeat, and attitudes towards interracial relationships reflecting those differing stereotypes).
Not a Chinese national (ethnic Chinese though, and my family comes from Singapore though I was raised in and live in Canada) but I think I'd chime in on this one- this US racism, or specifically, stereotyping, has spread as an international phenomenon; that is the predictable result of having a global empire whose strongest asset is- honestly, not its military (as massively bloated as it is) but its propaganda. This is not at all a Chinese-specific phenomenon, nor a Chinese-nationalistic phenomenon (as Chinese nationalists have nothing to gain from mentally putting down African-Americans an ocean away), and I'd argue is even wholly unrelated to the phenomenon of nationalism in general.
Black PoWs, in the age of the Korean war, or the Vietnam war, etc... also came along in the backdrop of African-American mainstream culture as it was, and how it was perceived across the world, in that time period; and I don't think it's exaggerating it to say that that, is a completely different story compared to how African-American culture presents itself to the world today, after the civil rights movement has been stripped of its teeth, its leading activists all killed, crack flooded into the streets, a very specific kind of "gangster" culture repugnant to most cultures' senses of propriety and decency is promoted as the face of black America, etc... I'm just calling it as it is- I have respect for someone so long as they're alright, personally- but let's not kid ourselves, there is a whole lot being promoted, by capitalist media, by primarily white-owned labels etc., that is incredibly... unrelatable to anyone who isn't looking to embody the worst aspects of the lumpenproletariat (of which I consider myself a part of), which is remarkably self-destructive, and which can also be considered a sort of pseudo-class traitor (or outright class-traitor) aspirations...
Myself not being black, I have some hesitation in typing this, but you have to understand that I'm not coming from a point of hate here. Hell, I've been homeless (and this culture is a serious issue, that primarily preys upon those disadvantaged, of minority communities, etc). Most people that would even be considered to be living "that life" can recognize there's some seriously unhealthy shit being promoted as the face of black America; and I've befriended them, and it rarely goes well, but even where it does it really is a self-destructive path not conducive to either living in capitalist society (unless you hit it big) nor living as a decent person who treats others with decency in turn, nor being a good comrade (frankly a lot of it is likely designed nowadays to divert people from such a path in the first place). Frankly, the CIA is running victory laps (saw someone say that before; repeating it here) at how they have destroyed the image, esteem, and values (no, I'm not talking "masculine/traditional/etc" values) of the black community.
The image of black America today is very, very different from what it once was, to sum it up. And while the rest of the world generally has sympathy for their plight- this stereotypical image has gone a long way in furthering the cause of division, which is what it was crafted for. Many Asian parents (not just Chinese) might warn their kids off from hanging around a certain crowd as an example, but the same goes for many African (immigrant) parents, as well as many African-American parents who either have "escaped the hood" or who aspire to do so. And that can be extrapolated on a global scale, and not just to parents as well- the truth is, with some people's vibes, sometimes you literally need to watch your stuff, or even outright your back (ie. your safety)- shit has gotten bad. This is undeniable.
And meanwhile, alongside all this, the imperial divide-and-conquer games continue. Back in the 60s and 70s, there would not generally have been a reason to drive Asians against Blacks and vice versa, for instance (save for in certain small regions with large populations of both- so some parts of the Caribbean, and Uganda's Indian population come to mind). Nowadays I think I can safely say that anti-Asian hate has been cultivated in a fair amount of the black diaspora (and vice versa- not black Africans though, they're a entirely different story in my experience) and mutual distrust, even if there is also room for a lot of solidarity and relations (which I've experienced) has festered between both communities. People aren't entirely ignorant, we (both the Asian diaspora, and Asians in Asia) can see these sorts of things and understand in some degree what is going on.
Hopefully that gives more context on the subject of your comment. I'm not justifying it whatsoever; but I'm simply saying that I don't think these stereotypes, in a Asian (and particularly mainland Asian) context, have anything to do with nationalism.
(edit) and this is before getting into the... mess that is the other side of the picture- the promotion of a token image of African-Americans, as the face of empire, to "blackwash" imperial crimes. Nowadays they usually send black delegates to the UN when it's about Palestine for instance, if you've noticed. The first black POTUS declared the "pivot to Asia," destroyed Africa's most prosperous country, and ramped up the atrocities against Muslims. Now there's Kamala Harris, that black (and Asian) slaver (yes, that is what she is), who is Genocide Joe's second-in-command (officially, in practice I imagine she's rather useless). On one hand there's an image of "black gangsterism" (no offense to the countless decent lumpen out there, and at least in some degree you gotta do what you gotta do) being promoted, then on the other hand there's an image of "black propriety" being promoted as well, which is just a black token face for the genocidal, imperialist machine... anyways you get the deal.