Preheat oven to 350 degrees.
Place pork roast into a Dutch oven. Sprinkle with spices, toss in the garlic and top with the onion rings. Pour in the beer and 1 cup of the green enchilada sauce.
Cook pork covered for two hours.
Remove from oven, let cool and and pour the contents of the Dutch Oven onto a large surface that you can fine shred the meat with two forks.
To build the enchiladas, working in two batches, wrap half of the corn tortillas in a clean dish cloth that's been slightly dampened with water under the faucet. Place wrapped tortillas in a gallon zip lock bag, but don't close the bag. Place in microwave and cook for 4 minutes on 50% power.
Coat a 9 x 13 casserole dish with Pam. Remove tortillas from bag and place about 1/4 cup of the shredded pork in a tortilla shell. Top with 2 Tablespoons of cheese and roll. Place the first enchilada into the casserole dish, seam side down, nestled to one edge of the pan. Repeat with the remaining tortillas, pressing them close together as you build and place them in the pan.
Heat the remaining tortillas and repeat the process.
Once all tortillas are filled and in casserole dish, pour remaining cup of enchilada sauce over the enchiladas and generously sprinkle with more Monterey Jack Cheese.
Bake 30 minutes covered or until bubbly.
Serve immediately.
*If you can't find ancho chile powder, just increase the regular chili powder to two teaspoons
** This can also be made in the crockpot. Follow directions for the Dutch oven and cook in slow cooker on low for 6 - 8 hours.