This is the wrong mental model for a few reasons, not least that breaking into the US market would require massive marketing and infrastructure investment that would have to be paid for. And that’s before you worry about reengineering for US regulations.
Also: The current Chinese EV market is not in a sustainable place. It’s the product of massive government investment and (over) incentive to produce. Most Chinese EV makers are headed to bankruptcy if current trends continue, so they won’t.
In the steady state, Chinese EVs with German-class tariffs would be competitive in the US but they wouldn’t blow the doors off the market any more than, say, Hyundai/Kia have.