A lot depends on the nature of the failure, but whatever the details the KMT is less a viable entity. When the Japanese come their task is easier vs a lesser KMT. As in OTL Japan can turn the remaining warlords into Satraps, Collaborationts. client states, ect... the difference here being there will be a few more of them and a bit stronger. The Communists may be in a better position as well.
There are a lot of possible butterfly effects post 1939. Perhaps the largest is the Japanese government sees no advantage to forcing its way into French Indochina. The original justification of that action was closing the import route to Chinese territory via the Haiphong port and the Red River basin. If this occurs then the US & Britain take no action, no embargo acts, no freezing Japanese business accounts in US banks, no other economic sanctions. Without any of that Japans economy can support another year or two, or maybe three of war with a weaker China. AND there is no reason for a Pacific war as we know it. If no Pacific war in 1942 - 43 the US can about double the overall combat power vs Europe in those years.