Cut chiles in half lengthwise; remove and discard seeds and membranes. Tear chiles into 2-inch pieces.
Combine chile pieces and boiling water in a bowl; cover and let stand 45 minutes.
Place chiles and water in container of an electric blender; cover and process until smooth, stopping once to scrape down sides.
Transfer mixture to a saucepan.
Add tomato sauce and next 5 ingredients. Bring to a boil; reduce heat, and simmer, uncovered, 10 minutes, stirring often. Spoon 1/2 cup tomato mixture into a 13- x 9- x 2-inch baking dish coated with cooking spray. Set remaining tomato mixture aside.
Combine meat and next 3 ingredients in a nonstick skillet; cook over medium heat until meat is browned, stirring until it crumbles.
Drain if necessary.
Add 1/2 cup tomato mixture and beans; stir well.
Spoon about 1/3 cup meat mixture across center of each tortilla.
Roll up tortillas; place, seam side down, over tomato mixture in baking dish.
Brush remaining tomato mixture over tortillas. Cover and bake at 350 for 20 minutes. Uncover and sprinkle with cheese; bake 3 to 5 additional minutes or until cheese melts.
To serve, place 1/2 cup lettuce and 1 enchilada on each plate. Top each with 2 tablespoons tomato and, if desired, sour cream.
