I honestly don't see, without a much earlier PoD, the KMT pushing Japan out of Korea, out of China, perhaps, but Korea was an integral
part of the Empire and as such would be able to be defended against the inferior (in terms of equipment and training) KMT.
Now, that all said if they do lose expect heads to roll, figuratively and literally for those who were in charge of the operations and such.
All in all, without having to worry about China I think Japan would go one of two ways;
1. Going 'neutral' and basically favouring whoever's winning during the course of WW2, being able to trade openly without the problems
(IE the American embargo) that occupying China caused.
2. Still join the Axis and go after European colonies, particularly Indonesia with even more zeal since they've lost the resources they were
getting from China.