Okay, but that's a totally different situation. German-Americans weren't occupied.
In an event of an AR, this will be a war. I'm not going to get into who's right and who's wrong, but PRC troops will be invading Taiwan and imposing their will on Taiwan. Many of the people they are occupying believe that they are being unjustly invaded and see PRC as invaders, occupiers, and looters.
Now how many will actively resist, or if they will resist is an open question. I've already explained my position pretty well I think. A tiny minority of people who will support an insurgency, and an even tinier minority of people who will actually be the insurgency, is still a large number of people who can cause quite a bit of havoc.
This might be the case, especially in an event of a protracted war with United States. I think Taiwan's military and Taiwan itself can fall and be occupied relatively shortly, but a war with United States and whoever decides to join, may last for many more months.
In that period, between when Taiwan's military is defeated, but when the wider war is not yet over, I believe will provide the greatest incentive for a potential insurgency, that could very well inflict serious setbacks for PRC's "occupation" of Taiwan.