BYD actively sells electric busses in the US. There was never a sanction to stop BYD or NIO (to my knowledge).
But diplomatic cables revealed by WikiLeaks and provided to Reuters by a third party, as well as interviews with industry consultants and executives who have examined the company’s operations, raise a number of questions about the fledgling carmaker. Among other things, they describe a record of stealing designs from rivals, using those savings to undercut competitors on price and scrimping on safety.
And oh... There's that