Heat oil in a large high-sided skillet set to medium heat. Add chicken; cook and stir 3 minutes. Add taco seasoning; cook for an additional 2 minutes or until chicken is no longer pink. Stir in salsa, beans, corn and 1 cup cheese.
Spread 1/2 cup enchilada sauce on bottom of 13x9-inch baking dish. Soften tortillas by placing inside a slightly damp paper towel, setting on a plate and microwaving for 30 seconds. Place 2/3 cup chicken mixture down center of each tortilla; roll up. Place in dish, seam-side-down.
Pour remaining sauce over tortillas; sprinkle with remaining cheese. Bake in preheated oven for 20 minutes, or until cheese is melted and filling is hot. Garnish with olives, green onions/cilantro and serve with sour cream, if desired.