I dunno.
I mean, Chiang's forces collapsed in 48 and 49. you might be thinking of his plan to finish them off in Harbin, but he was massively overextended. And was broke. And had no support.
Etc.
No, this is actually a different thing... although I was initially thinking of that. The impression given where I read about it isn't that he was overextended at all...
I would like a source for this. I had not heard it before and did not quickly find it on the net.
'China without Tears', by Arthur Waldron, in
What If? Military Historians Imagine What Might have Been, ed. Robert Cowley, 2001.
Maybe Waldron is in a minority of one in his view, I really don't know. It seemed plausible, though. Basically, he presents a couple of different scenarios, the most important of which (on re-reading) is actually that Chiang/Jiang
does not try to re-take Manchuria at all, instead leaving it for the Communists to have. Then, his forces would have been more concentrated, and it seems that both the US and USSR would have been, if not happy, then at least content with such a situation.The 'Chinese Democratic Republic' might have become another East Germany - but by marching on Manchuria (as Faeelin points out) he overextended his forces, and never quite finished them off.