There's next to no economic literature showing job losses for US citizens (which includes naturalized citizens) to illegal immigrants.
For reference on why your example makes no sense. We naturalize under a million people each year, yet we use over a million illegal laborers on farms alone, let alone other industries like hospitality or meat plants. There's literally not enough US citizens to do all the jobs the country wants done, and the GOP has also opposed legal immigration because their objections are racial, not economic.