Lightly grease a slow cooker. Add the pork roast, garlic, chipotle pepper, chicken broth, chili powder, cumin, salt and pepper.
Cover and cook on low for 5-6 hours. Remove pork from slow cooker and reserve 1/4 cup of the cooking liquid. Shred the meat with 2 forks. Taste and reseason with additional salt and pepper, if desired.
While the pork is cooking, make the sauce by combining all of the ingredients in a medium bowl. Refrigerate until you are ready to assemble the enchiladas.
Preheat oven to 350 degrees. Lightly grease a 9x13 inch baking dish. Spread about 1/2 cup of the sauce in the bottom of the dish.
Place about 1/4 cup of shredded pork down the center of each tortilla. Sprinkle with Monterrey Jack cheese (you should use about 1/2 of the cheese for the filling). Repeat with the remaining tortillas.
Place the filled tortillas in the prepared pan. Pour the remaining sauce over the tortillas and sprinkle with the remaining cheese.
Bake, covered with foil, for 20-25 minutes. Remove foil and bake for an additional 5-10 minutes, or until cheese is golden and bubbly.