Not the least of which being that if they nuke it, they don't get it. At least not in the way they want it.
But honestly, way theory aside, massive open warfare against Taiwan would be horrific for Taiwan, but outside of the region, it would really doom China as it exists.
Even if they did manage to take the island, likely with just an overwhelming wave of soldiers, at that point, the entire world, aside from a few exceptions (NK, Iran, Syria, Russia, Belarus, and maybe some African nations) are going to effectively strangle the Chinese economy with sanctions if not an outright embargo.
It might not change things overnight, but hitting China square in the economy is far more effective than it is for Russia, because China is so much more of a player in the world economy. They depend on the world buying their goods. As long as the rest of the world can keep unfulfilled consumer demand from triggering crippling sustained double digit inflation for years on end, there may not even be a need for large scale, near-peer open warfare.
While I won't touch the subject matter with a ten foot pole, since I have a take that neither side likes...
Christ on a bike, I felt that one in my bones!