Preheat oven to 350°F. Grease a 9x13-inch baking dish. In a large bowl, mix together the sour cream, cream of chicken soup, green chiles, chili powder, cumin, garlic powder, and salt. Reserve 1/2 cup of this mixture.

In a separate bowl, combine the shredded chicken with the reserved 1/2 cup of the sauce mixture.

Pour 1/2 cup of the green enchilada sauce into the bottom of the baking dish. Arrange 6 tortillas over the sauce, overlapping as needed.

Spread half of the chicken mixture evenly over the tortillas. Drizzle with 1/2 of the remaining sour cream mixture and 1/2 cup of green enchilada sauce. Sprinkle with 1/2 of the shredded cheese.

Add the remaining 6 tortillas. Spread the remaining chicken mixture evenly over the tortillas, followed by the rest of the sour cream mixture and green enchilada sauce. Sprinkle with the remaining cheese.

Cover with foil and bake for 25 minutes. Remove the foil and bake for an additional 10 minutes, or until bubbly and the cheese is melted.

Let stand for 10 minutes before serving. Garnish with cilantro, if desired.