The Chinese government is not loved. They are heavily dependent on resources brought in by sea (which we could interdict quite easily). We could block oil shipments and also take out hydroelectric dams and the country would have almost no power at all. Food shortages would result. Famine and revolution would create a massive die-off in a very short time.
We don't even need an army. No boots on that ground -- a land war in Asia is famously foolish. We could win at a distance.