Not the same way North Koreans are brainwashed. Chinese people have the ability to leave their country and visit other countries.
However, I feel mainland Chinese people are incredibly nationalistic. All peoples are nationalistic but I find them especially so. And you will find that a large majority of Chinese people think the following:
-they think that Taiwan belongs to China
-they think that China has the most beautiful women
-they think that Japanese are evil
-they always talk about their 5000 years of culture even though modern day China has little left of it
-Most Chinese are not aware of the Tiananmen square massacre at all
-Most Chinese still believe that Mao Zedong did more good than harm
-they think that Koreans stole their culture and the women are all plastic
-even though they are atheist they believe in superstitions for example feng shui or certain numbers etc
-They believe certain areas of China that were part of China thousands of years ago still belong to China today
-Chinese people seem to put a lot of faith into their government. I’ve seen them use extreme cases to justify certain questionable government decisions. For example, banning foreign websites: Foreigners think its extremely limiting to freedom but Chinese people think its a good thing because it protects their domestic industry. censoring sex/violence in entertainment: Foreigners think its extreme, Chinese people think that having sex/violence in entertainment will lead to people becoming depraved criminals. censoring social media: Foreigners think it limits freedom, Chinese people think having a free social media is too crazy and chaotic and unstable. The government makes them wear ugly track outfits for school. Foreigners think Korean/Japanese school uniforms look better. Chinese people think its distracts them from studying and looks too sexy. Chinese people seem to place a premium on stability and harmony over freedom and flexibility, I think.
In other ways they are not brainwashed but I do find them to be close minded in this sense, they accept certain things to be true about other countries or cultures without any empirical evidence.