Place pork into a crockpot. Slice the peppers and onion; add 1 pepper and the onion to the crockpot. Dice the remaining pepper slices; cover and refrigerate for later.
Mix peanut butter, soy sauce, cumin, broth, and the juice of the lime in a small bowl; pour over pork and veggies.
Cook on low for 6-8 hours; check for doneness after 6 hours.
Before serving, cook rice as directed on package. Shred pork; toss with sauce from the crockpot. Serve over rice, topped with chopped peanuts, sliced green onions, and diced raw pepper. Serve mangoes on the side.