I'm hunting back to the beginning.
Okay, seems like in the later parts of the previous timeline, Nixon's China initiative was shut down hard after Nixon was taken out of office and a hard line Agnew administration came in. The subsequent administrations continued the hard line policy in terms of dealing with China. The failure of Nixon's venture resulted in the disgrace or loss of face of Chinese moderates like Chou En Lai and Deng Xioao Peng. Their stars dropped, and other rivals and hard liners rose instead.
China came under the control of someone known as the 'Lesser Mao', a nephew of Mao Tse Tung who ruled in the name of the sick and dying Mao. He outmaneuvered Mao's wife, Chiang Ching, herself discredited somewhat by the Cultural revolution, and Chou En Lai's damaged faction, and parlayed his access to and influence over Mao into political dominance. He continued to rule through his uncle, concealing the death of Mao. He seems to have been a right nutter, mismanaging the place even more catastrophically than Mao. Insecure about his position, which was based on authority derived from a sick and dying man (and then concealing that death to maintain his authority) he gave full vent to paranoia, continually purging anything and anyone around him, in a manner reminiscent of the excesses of Stalin, Pol Pot, the French Revolution's 'Terror.' Surrounded by sycophants the regime retreated into unreality and delusion, buoyed by perpetual purges to the point of randomness. Information and administration systems broke down.
The Lesser Mao, without any grounding in practical reality, embraced ideological extremism, deciding that things like literacy were counter-revolutionary and must be purged. The regime seems to have sustained itself somewhat by massive heroin cultivation and production, with a heroin epidemic hitting America. But these were one of the few successes of his regime. There was a short disastrous war with the USSR over Mongolia in 1973. Then following America's resolution of its Indochinese war, the Lesser Mao chose to invade Indochina himself, coming into conflict with Thailand, Laos, Cambodia and North and South Vietnam. In OTL China had invaded Vietnam in 1982, but gave it up as a bad job. In this timeline, the Lesser Mao regime was so removed from reality that literally, there was no one in China who could come back and report that it was a disaster. Instead, failure was not an option, and China continued to grind away disastrously, far beyond its logistical abilities, its soldiers literally unsupplied and starving.
Things went badly, badly off the rails. As a result of famines based on mismanagement, there was a major revolt of army divisions, including those involved in the Indochina war. The Lesser Mao used nuclear weapon on them at Kwangsi, a heavily populated area. He then blamed the United States for the nuclear strike, using captured American prisoners from Vietnam. The Americans, with tacit consent of the Soviets, launched a pre-emptive nuclear strike to destroy the Chinese nuclear weapons facility at Lop Nol. A full scale war between China and America largely failed to appear because the unwillingness of the Americans to follow up, and the inability of the Chinese to respond. This appears to have split the Chinese Communist party into open revolt, but this was too little too late, as the Chinese administrative structure had been so thoroughly and relentlessly repeatedly purged that it more or less disintegrated into rotten cloth. The Communist Chinese regime seems to have dissolved into civil war and then warlordism, with a complete social breakdown. There were apparently releases of biological weapons as well as atomic weapons. Infrastructure breakdown and fighting brought about mass starvation, and the effective collapse of the Chinese state. Whole cities were depopulated, immense numbers of Chinese died, survivors reported cannibalism to survive.
Addressing the humanitarian crisis, an international response was begun, which seems to have been a cover for the dismemberment of China. Tibet fell out of the Chinese sphere, but seems to have fallen under the control of India. Meanwhile, Pakistan, encroaching or revising its borders with China came into conflict with India, which seems to have eventually lead to war between the two countries. A war where, with covert US assistance and major Indian mismanagement, Pakistan did very well in.
The Soviet Union intervened in border areas, Szechuan, Manchuria and Inner Mongolia, but avoided the interior and population centers, not wanting to be drawn into a quagmire. They supported a rump communist state on the Northeast, but overall seemed to keep their hands out. In the late eighties, they're pretty much standing idly by while North Korea bites chunks out of Manchuria. In the Chinese center and west, Muslim missionaries have managed to stabilize regions and provide for and convert the population, forming an Ad Hoc 'Islamic Republic of China.' The Russians seem unwilling to quash it, and the rump communists are unable to displace it. Even this implies more stability, as both the Islamic Republic and Rump communist state seem to be ramshackle affairs with warlords, dissidents and opportunists running wild through the region.
In the South, Burma seems to have moved into some territory, but its position is stable. Vietnam has advanced into the south of China, securing territory which borders on territories overrun by Taiwan/Kuomintang which now has mainland pretensions of being the true government of China. Meanwhile North of the Taiwan/Kuomintang territories, the South Koreans have occupied large territories. Originally, Taiwan and South Korea were junior partners of an international relief effort lead by the United States and Britain, supported by Australia, New Zealand and Japan. However, American policy through the 80's seems to have been to reduce its commitment while selling arms and sewing dissension among South Korea, Taiwan/China and North Vietnam. By the mid to late eighties, Taiwan/China and South Korea in particular have been fighting an increasingly hot undeclared war. Britain is holding onto Hong Kong and some adjacent territories, my impression is that they're overwhelmed, don't want to be there, but have no way out, so their strategy is to keep their head down as the othe parties duke it out and hope for the best. Australia and New Zealand seem to have gone home, or perhaps are rump humanitarian presences or supporting Hong Kong. The US may be holding onto a few strategic positions, but mainly seems to be stirring the pot. In the early 80's it adopted a Cheney Doctrine of attempting to break potential rivals into small states, working actively to trigger separatist movements and internal crises in India, Brazil, Britain and Canada. China was ground zero for this policy. Japan, because of its history with WWII wasn't welcome as an active player in the international consortium, and has become less and less interested in China over time. Japan's current strategy seems to be to let South Korea and Taiwan/China duke it out, rebuild its navy, re-orient its foreign policy.
Overall, China seems to have been badly damaged by the Lesser Mao period. Lots of references to collapsed and degraded infrastructure, roads being impassable for lack of maintenance, famines, plagues, disruptions, civil wars, foreign invasions. We're looking at a death toll in the hundreds of millions over the last decade, no one knows how many, but 200 million is minimum and my own assessment is probably double that. There are multiple claimants, at least two, maybe four or more, for the title of 'Chinese State' none of whom come near to ruling the whole country, and greater or lesser foreign occupations encroachments by North Korea, South Korea, the USSR, India, Pakistan, Burma, Britain and the United States, some of which are going to war with each other on Chinese soil. China is a mess.