Loin is not a good choice for chile verde, especially if you are going to cook it first--then again when the sauce is made. It doesn't have the fat to support the double-cooking.
If you really want to use loin then I'd smoke/roast at ~325 to an internal temp of 140. Rest 30 min. Slice thickly, cube, then add to the verde (along with any juices that collect when the pork rests) but add only near the end. Keep the sauce at 160-170 degrees tops (just below a simmer), stirring frequently, for maybe 10 min or so; serve.