I read up a bit into this a few year ago and China invading Taiwan is actually far harder than you'd think. There are only a few easily fortified areas that can handle an amphibious assault, and either way PLA has limited amphibious assault capability and limited modern warfighting experience (PLA is actually suprisingly corrupt and ineffective).

Of course, during a war military planners expect massive cyber attacks against Taiwan, and CCP sympathizers within Taiwan committing sabotage. Military planners also expect NATO forces to use missile barrages against targets on the mainland of China (which would clearly cause escalation).

The threat of nuclear war goes both ways: the impact of nuclear on discouraging the defence of Taiwan is equally applicable on discouraging the invasion of Taiwan.