Back in the 1960s Chairman Mao used to bluster about how the Chinese could win a nuclear war. Their population was so large that they would still be around when all the rest of the world would be dead. And then they could start with a blank slate to build socialism for the workers and peasants with no rotten capitalism around to spoil things.
China has 90% of their population concentrated in 15% of their territory. A nuclear war would virtually eradicate them and they know it.
Just more bluster like this flaccid and tiresome bleating from the Soviets.