I doubt that the PRC is willing to invade TW if TW had sufficient nuclear weapons. The thought of the two sides nuking each other is pretty horrific, including to the PRC side. So its an effective deterrent - but its too late. As soon as China detects budding nuclear capability they will be forced to invade ready or not.

Then again, you can make the argument that if TW/US/JPN feel now is the best time to resolve the situation in their favor and prevent future threats vs TW, they could start transferring nukes to TW, trigger a war, beat back the invasion, and make a nuclear and independent TW a fair accompli.

However,all of that is a pipe dream - there is no political will anywhere to trigger a war now. Everyone wants to kick the can down the road and hope the other side weakens enough to no longer pose a threat