I wonder how much the people who are voting for a nationalist victory actually know about the Chinese Civil War. The key elements of communist victory, that is their positively
massive political support among the Chinese populace and the base camps set-up throughout eastern China inside territory occupied by the Japanese, were already in place by February of 1945. So the communists are still favored to win.
It was not. The quantity of IJA weaponry turned over to the Communists paled in comparison to the steady stream of American-made weaponry the Communists were able to either steal or buy from the corrupt nationalist camp (Mao at one point declared that Chiang Kai-Shek was "our supply officer") and much of the more technically complex gear (namely tanks and artillery) was unusable until enough nationalist Chinese troops who actually had the skills to use them defected to the communists.
The KMT then became badly over-extended trying to retake Manchuria which led to their collapse.
What led to the KMT's collapse was their corruption, incompetence, and ineffectiveness as a government leading them to become horribly unpopular among the Chinese population. This led to entire armies defecting to the communists side. The Manchurian overextension was useful to the communists, but it was hardly vital. It's liable to happen anyways as well... as it was, the nationalists had to beg the Soviets to stay for several actual months in order to keep order in Manchuria because their own armies simply could not move north fast enough. Despite the Americans going out of their way to airlift some nationalist units north, the nationalists simply could not move fast enough to secure Manchuria before the communists. One constant of the Chinese Civil War was of Communist formations superior mobility over that of their nationalist counterparts: they were trained to move faster and over terrain the nationalists couldn't. A sudden Japanese surrender in February of 1945 is liable to result in a massive vacuum across northeast China (not just Manchuria) which the Communists are in a better position to fill before the nationalists can. Then all the communists have to do is lie low and let the nationalists in so that when the fighting actually starts they can then cut them off and destroy them... assuming they don't just switch sides like many nationalist formations did in such situations.
Almost the entire county? Hardly. "By the time of their 1945 surrender,. Mao's party-army held sway over almost 100 million people mainly in North, Northeast, and North Central China."
It should further be noted that even in areas that were officially under nationalist control, there were large communist base camps set-up with significant guerrilla forces embedded within the populace. These forces simply lied in wait until the opportune moment when they could rise-up and seize control of the region. And the communist leadership was very good at timing these uprisings for moments where they would cut-off the maximum number of nationalist troops.