Chicken Enchilada Casserole

This is one of my Gregory's favorites!

1 medium onion diced small
2 TBS vegetable oil
1 dozen medium corn tortillas
4 C. shredded, cooked Chicken
1 can (15oz) tomato sauce
1 can (14 1/2oz) peeled tomatoes undrained, cut up
1 can green chilies (optional)
2 cans (2 1/4oz) sliced ripe olives, drained
3 C. grated Monterey Jack cheese
1 pkg. Lawry's Taco Seasoning
1/2 tsp Garlic powder

In a large skillet, saute onion in oil. Add chicken, tomato sauce, tomatoes, taco seasoning and garlic powder; blend well. Bring to a boil, then reduce heat and simmer uncovered for 15 mins. In a 13x9x2 in glass baking dish (spray with cooking spray for easy clean up), place 4 to 6 tortillas. Pour 1/3 of chicken mixture on tortillas spreading evenly. Layer with 1/3 of olives, and a 1/3 of cheese. Repeat layers 2 more times, ending with the cheese. Bake uncovered in a 350 degree oven for 30 to 40 minutes or until heated through and cheese melts (I usually bake it for about 20).
Makes about 8 servings. For a bigger crowd, double the recipe.
Serve with sour cream, mexican rice and salad