Cut the Chuck Roast into 1 to 2 inch cubes, trimming off as much fat as you can. Place the beef into a crock pot and add the enchilada sauce, onion, green chiles, garlic, and bouillon cubes. Give it a good stir, cover and cook on low 7-8 hours. (or high for 3-4 hours). Check the beef and add salt and pepper to taste.
Shred the beef slightly with two forks, leaving it in the sauce for now.
Prepare The Burritos:
Spoon a couple tablespoons of beans on each tortilla. Remove some beef from the crock pot with a slotted spoon and place on top of the beans.
Fold the burrito up, top with plenty of sauce from the crock pot and then add cheese on top. Place under the broiler till the cheese is melted and bubbly.