Rinse chicken breast halves and pat dry with paper towels.
In a large saucepan, combine chicken, 2/3 cup of the onion, the cilantro, half of the red chili peppers, half of the jalapeno peppers, the chili powder, and garlic. Add enough water to cover chicken. Bring to boiling; reduce heat.
Simmer, covered, for 15 to 20 minutes or until chicken is no longer pink in center. Remove chicken and shred. Discard the cooking liquid.
In a large skillet, heat the 1 tablespoon oil over medium-high heat. Add remaining onion, remaining red chili peppers, and remaining jalapeno peppers. Add shredded chicken, 1/2 cup of the enchilada sauce, and the green chili peppers. Bring to boiling; reduce heat.
Simmer the chicken mixture, covered, for 15 minutes, stirring occasionally. Keep warm.
In a medium skillet, heat the 1 cup oil. Working quickly, fry tortillas, one at a time, in hot oil for 10 to 15 seconds or until tortilla is hot but not crisp. Pat dry between paper towels.
Immediately place about 1/3 cup chicken mixture onto each tortilla near an edge; roll up. Place filled tortillas, seam sides down, in a lightly greased 2-quart rectangular baking dish. Pour remaining enchilada sauce over. Cover with foil.
Bake in a 350 degrees oven for 20 to 25 minutes or until heated through. Uncover; sprinkle cheeses over. Return to oven and bake for 2 to 3 minutes more or until cheeses are melted. To serve, sprinkle with olives and green onions. Serve with sour cream and guacamole, if desired. Makes 5 servings.