There are exceptions, and I saw nothing in the opinions that made it obvious that the Court would reject legislation that dealt with temporary visitors. The POTUS can't do it; that's obvious. They might get the votes for something where the child of two non-citizen, non-resident parents would only get citizenship if the child and the parents (maybe you need both) stayed in the country legally for X days.

This could address birth tourism and the "accidental" birth to people here temporarily but not for the purpose of having a child. That would include the parents of US soccer player Balogun, who were here visiting and then returned to England.