Place the pork in a deep, heavy stockpot or crockpot. (I used a crockpot).
Add the chicken stock and enough water to completely cover it.
Drop in the garlic and stir in the chili powders, black pepper and salt.
Cover the pot and bring the mixture to a low simmer over medium heat.
Let the pork braise in the liquid for at least 6 hours and up to 8 hours.
Remove the pork from the braising liquid.
Using your hands or 2 forks, pull the meat into strands and place in a bowl.
Skim garlic cloves from pot and squish them up with the meat.
*Note* I changed direction right here - instead of the enchilada sauce, I dipped out about 3 cups of braising liquid & put in a saucepan. I whisked in 3 tablespoons of cornstarch & let it cook till thick.
Stir about 1 cup of enchilada sauce into the pork.
Heat the oven to 400F°.
Spoon a few tablespoons of enchilada sauce in the bottom of a 9 x 13 baking dish. Spread the sauce so that it coats the bottom of the entire dish.
Spoon some of the pork onto the middle of a tortilla, roll it up, tucking in the sides as you roll, and place seam side down in the baking dish.
Continue to fill the remaining tortillas and place them in the baking dish.
Pour more enchilada sauce on top of the tortillas so that they are covered.
Cover and bake for 20 minutes or until heated through.
To serve, place a rolled enchilada on a serving plate and spoon some more sauce over the top.
Garnish with cilantro, chopped green onions, crumbled cheese & sour cream.