As Jeremy Lin said - post-WWII, the assumed outcome of the Chinese Civil War was the Communists bottled up it Manchuria under Soviet protection and Chiang overlord of the rest. However, Stalin, ever unimpressed by Mao, was planning on pulling out after concessions and letting the KMT roll into town. The Communists were so complacent they spent 1945/6 setting up local party offices and designing stamps for their Marxist 'North China'. However Chiang was hampered by Marshall and his stop-start course and a changing international situation allowed the Communists to rearm rapidly and go on the offensive.
Chiang never trusted Stalin but in doesn't mean he's uninterested in doing business with him.
North Korea will be interesting if Stalin and Chiang agree to screw Mao and Manchuria falls to the KMT. After all, its still a Soviet zone of occupation, and you know how they usually turn out. No Mao does weaken Soviet confidence they can get away with an invasion of South Korea by proxy - not sure.
Vietnam however, oh boy does that get interesting! Chiang took inspiration from many political ideologies but one was definately anti-colonialism. The Viet Minh and its predecessors had his full backing against the French and then the Japanese, and will certainly have it against the French yet again. How the Americans deal with that, is a very interesting question. It one thing to oppose international Communism, its another to choose between two allied powers, one anti-communist and a developing 'democracy', the other a declining colonial power with the occassional communist minister.
Given the timing of the Indochinese War and Suez (Nasser still has good odds with a 1945/6 PoD in China), it might see an early French split with NATO if the Americans back China's horse. If Chiang helped stop a Korean War, the White House might even feel they owe him and demand Paris just give up. In turn this has the interesting knock on that Ho Chi Minh or whoever might install a bog standard NAM pseudo-socialist republic rather than full blooded Marxist-Leninist state, one open to cooperation with the highest bidder...
Actually Nasser might be a decent comparison to how Chiang could play the superpowers. Prior to Suez, Nasser openly admitted he was accepting a bidding war. However Egypt is not China, and Chiang might have much more room to mess around with the superpowers.
On Tibet, the KMT might take a more softly softly approach but who knows. Xinjiang is interesting, with that AND Manchuria, Stalin might ask for some decent concessions, possibly (a guess based on his neo-Tsarist foreign policy) basing rights at Harbin/Port Arthur? Certainly investment oppourtunities, possibly keeping an influence in Manchurian resources.
Ironically I can see US idealism towards her 'third world' ally, a wish to pull back post-war and their approach to Japan, could all make Chiang become a major nuisance to America's early Cold War effort, even more than the PRC due to their UN seat and a more ambiguous position.
This will probably mean more Soviet interest in the Middle East, and perhaps an earlier crack at Africa. After all, Moscow seems to have missed the opportunity to get in on the hullaballoo of decolonisation IOTL, leaving it til the 1970s to give it a good old go.
Chinese culture/society? Well we'll see Chinese cinema bleed into the Western conscience earlier. Perhaps an earlier interest in Eastern philosophy and spirtuality? Hong Kong and Macau could get interesting. When India goes for Goa, Chiang might seize Macau. Though I doubt he'd try for Hong Kong. However nationalism might be stronger in the city, and the Republic might be able to push for stronger cross-border institutions earlier on.