Preheat oven to 350 degrees. Lightly grease a 9 x 13 baking dish.
In a large skillet over medium high heat, cook onion with 1 TBS cooking oil until onions are softened and lightly browned. Stir in taco seasoning, cooked chicken and 1/4 cup of water. Turn off burner.
In a medium bowl combine enchilada sauce and sour cream until smooth.
Place 1/4 cup of enchilada sour cream sauce and spread evenly into prepared baking dish.
Layer 1/2 of the corn tortillas over sauce. Spread 1/2 of chicken mixture on top of corn tortillas evenly. Pour half of enchilada sour cream sauce evenly over chicken. Sprinkle half of the shredded cheese over the enchilada sour cream sauce.
Place remainder tortillas on top of shredded cheese. Spread rest of chicken mixture on top of tortillas. Pour reminder enchilada sour cream sauce on top of chicken. Sprinkle with remainder of cheese.
Bake uncovered for 25-30 minutes until cheese is melted and casserole is heated through. Cool for 10 minutes before serving with garnishes.
Catherine I love your recipes thank you for sharing them.