Good news is the peppers mellowed overnight, so the leftovers weren't too hot. Looks like it's called "caldillo" and can be done either with pork or beef. I was just reverse-engineering what I've had and hoping for the best, no official recipe was used.

Brown some pork stew meat in olive oil, put in a small crock pot if just using one pound. Cut an onion (or more for a larger batch) (vidalia this time) in vertical strips rather than rings, saute in a bit more oil til partly caramelized. Add (peeled) hatch chilis cut in large bites, no seeds, perhaps 1/2 cup worth. Sprinkle with salt, pepper, a little dried red chili (pure not chili powder), ditto ground cumin. No added liquid was necessary. Stir, set on low, walk away, 6 hours on low seemed to work fine. If you think your ingredients might be dry check on it, make sure it doesn't need a bit of water or tomato for liquid.

Serving time: either bake or steam a white potato. Scoop out of the skin, cut into chunks, stick in a soup bowl, pour the stuff over. (you could include the taters in the crock earlier,but I like the texture of this method better).