Green Enchilada Casserole

This is my go to dish if I need to pull off dinner in an instant.  It's quick and easy, super yummy, and makes for great left overs.  Everyone in the family likes it and cleans their plates when I serve it up.  I think I might even make it tonight.  (My recipe calls for a lot of canned items, that's because  what I like about this casserole is how quickly I can pull it together.  However, you could definitely substitute canned items for homemade if you have the time.)  You've got to give it a try!  Here's the DL...
2 Tablespoons butter
1/2 onion, diced
4 cups chopped cooked chicken
1 can (10 oz) green enchilada sauce
1 can (10.75 oz) cream of chicken soup
1 can (4 oz) diced green chilies
1 cup sour cream
1/2 teaspoon garlic powder
1/2 teaspoon cumin
9 corn tortillas
2 cups grated Montery Jack cheese
2 cups gated Cheddar cheese (or instead of both cheese, 4 cups Mexican cheese blend)
Preheat oven to 350 degrees.
In saucepan over medium heat melt butter.  Add onion and cook for 8 minutes, or until translucent.  Set aside.
Fill a medium size bowl with water.  Emmerse tortillas into the water.  Set aside.
Mix the two cheeses together.  Set aside.
In a medium bowl mix enchilada sauce, cream of chicken soup, green chilies, sour cream, garlic, and cumin.  Reserve 1 cup, set aside.
Add chicken and onion to the remaining sour cream mixture.
Spray the bottom of a 9 inch by 13 inch baking dish.  Spread the cup of reserved sour cream mixture evenly in baking dish.
Place three tortillas down, you can tear them apart to fit, but try not to overlap them.  Evenly spread a third of the chicken mixture on top.  Sprinkle on 1 cup of the cheese blend.  Repeat the tortilla, chicken, and cheese layers 2 more times.   Sprinkle remaining cup of cheese on top.
Bake for 30 to 45 minutes, or until bubbly.  Serve in squares and enjoy!  (serves 6-8)