Starting with the Enchilada Meat, coat the roast liberally with the taco seasoning.
Cook the roast in a crock pot on low for 6-8 hours until tender enough to shred. Remove the meat from the crock pot to cool, reserving the juice in the pot. When cool, shred the meat and add the juice to the Enchilada Sauce.
To make the Enchilada Sauce, sauté the onion and garlic in hot oil until soft.
Add the rest of the ingredients and simmer for 30 minutes
To make the Enchiladas
Pour some of the enchilada sauce in the bottom of the baking dish and cover evenly.
Pour 1/3 of the enchilada sauce into a pie plate.
Spray tortillas with cooking spray and heat quickly in a sauté pan. Stack the tortillas as they are done and then proceed to put the enchiladas together.
Dip the tortillas, one at a time, into the sauce in the pie plan to coat both sides.
Using a slotted spoon, add some beef mixture evenly down the center of each tortilla, sprinkle some cheese, some chiles, and pour a little enchilada sauce on the beef and roll up (optionally, add some refried beans and/or sweet corn).
Place the beef enchiladas seam-side down in a 13x9-inch baking dish.
(These can be covered and chilled for up to 24 hours and then bake for a total of 45 minutes.)
Cover the dish and bake in a 350 degree F oven for 15 minutes. Uncover the enchiladas. Spoon the remaining enchilada sauce over the beef enchiladas. Sprinkle with the cheese, and sliced black olives. Continue baking uncovered for 10 minutes or until the cheese is melted. Sprinkle liberally with cilantro and serve with sour cream.