Preheat oven to 350 degrees F. Cook pasta according to package directions; drain. Rinse; drain and set aside.
In skillet cook sweet peppers, onion, jalapeno, and 1/4 tsp. salt in hot oil over medium heat for 5 minutes or until tender. Stir in chicken, beans, taco seasoning mix, and 1/2 cup enchilada sauce. Cook and stir 5 minutes. Stir in 1/2 cup each of the cheese and green onions.
Divide filling among shells. Spread 1 cup of the remaining enchilada sauce in 3-quart rectangular baking dish. Arrange shells atop sauce. Drizzle with remaining enchilada sauce.
Bake, covered, for 30 minutes. Uncover; sprinkle with remaining cheese. Bake 5 minutes more or until cheese is melted. Sprinkle with chips and remaining green onions. Serve with avocado dip and/or sour cream. Makes 8 to 10 servings.