Depending on how the law is written this may be legal even under US law.
For instance if the law bans US companies from exporting/selling some chips to Chinese companies and that's it then it is unclear to me whether a Chinese company would do anything illegal under US law by buying such chips as it would be for the American seller to refuse.
Anyway, usually this sort of things takes place through intermediaries in third countries so it is difficult to track but obviously it would be stupid to brag about it if that happened.
For instance if the law bans US companies from exporting/selling some chips to Chinese companies and that's it then it is unclear to me whether a Chinese company would do anything illegal under US law by buying such chips as it would be for the American seller to refuse.
Anyway, usually this sort of things takes place through intermediaries in third countries so it is difficult to track but obviously it would be stupid to brag about it if that happened.