Chevron deference has little to nothing to do with constitutionality. It is a principle that says when Congress makes (ambiguous) laws and executive bodies inte

Chevron deference has little to nothing to do with constitutionality. It is a principle that says when Congress makes (ambiguous) laws and executive bodies interpret them according to their best judgment (having come to that judgment through an orderly and open process) the judiciary will defer to that executive body's judgment that they are following congressional intent. If something CBP does is challenged on its constitutionality the court doesn't need to go to Chevron, it will say that the enabling legislation is unconstitutional.