In large pot, boil chicken in water to cover until tender; reserve 2 cups broth. Debone and dice chicken. Add chicken, tomatoes, onion, salt and garlic to reserved broth; boil 10 minutes or until reduced enough for enchilada filling. Strain. Heat a bit of oil in a small skillet; press each tortillas into the hot oil a few seconds to soften them and make them more pliable to roll. Stuff with chicken filling. Roll filled tortillas and place in baking dish. Cover one-third of the enchiladas (longways) with salsa verde, the center third with the sour cream, and the final third with salsa colorado. The result should resemble the Mexican flag. Bake at 375 degrees until thoroughly heated, about 25 minutes. Salsa colorado: Wash chiles, stem and seed. Cook in boiling water to cover well 10 mins. or until soft. Remove and drain. Reserve liquid. Place chiles in blender with reserved water, and whirl until you achieve a pasty consistency. Heat oil in large skillet. Add garlic and flour and cook, stirring until flour browns. Add chile paste slowly to mix well with flour to a smooth paste. When all the chile paste is added, bring to a boil, stirring constantly. Cook until it thickens, 3-4 minutes. Thin with water to a thick, saucy consistency. Salsa verde: Boil tomatillos in small amount of water until tender; blend in food processor. In skillet, saute onions in oil. Add pureed tomatillos, salt and garlic.