I really don't get this. Congress expressly gave to the President the power to limit/restrict immigration, and he's exercising it. That's exactly what he's supposed to be doing. It's a far cry from Obama refusing to enforce valid laws that were actually on the books, which is surely something Congress did not intend.
And in terms of NAFTA...I don't recall the media being upset when Jimmy Carter unilaterally abrogated the Sino-American Mutual Defense Treaty with Taiwan in 1979. And the case for the President's right to withdraw from NAFTA is even stronger than the argument Carter had, because of the Congressional delegation of trade power to the President in the Trade Act of 1974.