After World War II, these forces of former Japanese puppet regimes once again returned to the nationalist camp for the same reason they defected to the Japanese invaders. Obviously, it was difficult for Chiang to immediately get rid of these warlords for good as soon as they surrendered to Chiang and rejoined the nationalists, because such a move would have alienated other factions within the nationalist ranks, and these former Japanese puppet regime's warlords could still help the nationalists to gain more territories by holding on to what was under their control until Chiang completed the deployment of his own troops to take over.
Following World War II, these forces from former Japanese puppet regimes rejoined the nationalist camp for the same reason they had defected to the invaders. It was difficult for Chiang to immediately get rid of these warlords completely after their surrender and rejoining because doing so would have alienated other factions within the nationalist ranks, and these former puppet regime's warlords could still help in gaining more territories by retaining control over what they previously managed until Chiang deployed his troops.