This is a fun little fault line, because leftists can take both sides. They can be for it because obviously America First is some racist bullshit. Or they can be against it, because H1B's are used by evil corporations to depress wages.
Anyway, from what I've read, and from what I know how the world works, the latter option is much more convincing. And it's buttressed by my working for a very large corporation that had its entire IT Support staff come from India, including entry-level support staff that could easily have been filled by native workers.
And, that said, I think the dividing line between authoritarianism and fascism might have something to do with fascists being willing to lose money for corporations, and this tells me that we are definitevely entering an explicitly fascist era, so I am not celebrating.