Loosely ball up some aluminum foil and cover the bottom of the crock pot. Place your rubbed roast on the aluminum and add nothing else! Cook high for 6 hours. The crock pot works like an oven or a grill with no liquid and the roast elevated.
Roast your chilies under the broiler for 15 minutes or until skin is blackened and scorched. Put them immediately in a plastic bag for a half hour, in order to sweat the skins off. Then wash each chili under cold water and remove left over skin, remove stem and clean out seeds. Put aside.
After 6 hours, remove the roast and the aluminum foil. Add the chilies to the crock pot. Add roast right back on top of the chilies still on high heat. At about 7 hours remove the roast and let sit for 20 minutes or so and then slice and add along with onion, back to the chilies and now broth that was made. Let cook enough to heat the pork again..... and the pork slices will all get a spicy flavor! The chilies will now look like the consistency of cooked spinach. Serve over rice with tortillas and sour cream. Seriously Yum!