He'll need a navy to do this first, and then he will have to contend with the US Navy, which won't be easy. Maybe you can get some sort of a back room deal made between Washington and Moscow, the US won't support Taiwan if the Soviets withdrawal from North Korea, and perhaps the Soviets withdrawal support from Greece and agree to look the other way while US supported rebels topple the Communist government in Albania. None of these situations are very likely as neither side was willing to part with what it already had.
The only other thing I can think of is to kill Stalin off either during WWII or just after it, the new Soviet leadership has more sense and does not want to stand toe to toe with the US and has an agreement with Washington to allow all of Eastern Europe to have any form of government they desire, and agrees to let the United States occupy the entire Korean peninsula. Without Cold War tensions, the US Navy is not as likely to get involved in the Chinese Civil War if Mao goes after Taiwan.
The Kuomintang flees to San Francisco and sets up a government in exile which is only recognized by Chinese-Americans.