Not really. The entire Tibet Autonomous Region has less than 4 million people living in it. Xinjiang is 26 million which is of course a lot but still insignificant compared to China's total population (and almost half the people living there are ethnically Chinese anyway).

Those regions might be politically important to China but demographically and economically (besides any potential natural resources) they hardly matter.

Han make up 91% of the population of China, in the USSR Russians were barely above 50%.

I mean China is a nation state that engages in some imperialism. The USSR was an empire first and foremost.

>nations with their own language and culture

There are few countries where there is a single language and culture. Just looking at Western Europe, there is Basques in Spain, Bretons in France, Welsh/Scottish in the UK, Frisians in Netherlands, Lombards in Italy, Walloons in Belgium etc etc.

>it weren’t for force and oppression.

Nah. That's USAID propaganda.

It's important to note that in the marxist/sociological tradition (doesn't really matter how actually marxist they are these days), "nation" refers to basically ethnicity. China itself claims to host 56 nations. In this context "nationalism" is considered a threat to the state and to the people. Don't confuse thus with pro-state patriotism, of course, which is alive and thriving.

The soviet union was the same way. Even member states mostly represented multiple nations, which often crossed member state borders.

Here's the relevant work from Stalin: "Marxism and the National Question": https://www.marxists.org/reference/archive/stalin/works/1913...

I'm pretty skeptical myself that nationalism was the thing that tore the soviet union apart. The most ethnically diverse areas (notably, georgia and central asia) generally benefitted the most from attachment to the soviet union. Surely here in the US we are less bound together by shared culture than the soviets ever were. If the soviets were an empire of nations, we are a prison-ship of them.