The only way this could happen is if the KMT somehow got weakened, like say by a large-scale war with Japan, or the western powers continuing to chip away at China like with the Qing.
The former would require a major shift, though not necessarily ASB or requiring a pre-1900 PoD, in Japanese strategic planning, which prioritized naval spending over the army (Korea notwithstanding). The latter is something European economies could not afford after WWI, and their financial obligations to America (which has always upheld Open Door) made resumption of those policies during the economic prosperity of the 20s an unwise prospect.
Alternatively, Mao and the CPP could have expanded underground with Soviet assistance, and later on launched a large-scale uprising with Soviet support. The former isn't quite impossible or even improbable, landowners and big business held a problematically-large amount of clout in the early days of the KMT, but the latter is rather...contrived. For one thing, large-scale intervention in China would necessitate transferring assets from European Russia to Siberia, and something Stalin would never have risked, and it would have provoked Japan and America. With the threat of Germany to the west, even if it was no longer the Great Power it once was, the Soviets could not have afforded major war with an emerging Great Power like China, and a full-fledged one (Japan) likely backed by at least one other Great Power (America). And Stalin knew it.
Mao never really had a chance, barring an...improbable, series of PoDs.