Preheat oven to 350°F (180°C). Grease a 2-quart baking dish.
Spread ¼ cup of the enchilada sauce in a thin layer in the bottom of the dish.
In a large bowl, stir together the chicken, chopped green chiles, ½ cup of the enchilada sauce, all of the sour cream, and about half of the cheese (½ cup). Taste and season with salt and pepper.
Place 4 of the tortillas in the bottom of the prepared dish, tearing or overlapping them as necessary to cover the bottom.
Top with half of the chicken mixture. Repeat with another layer of tortillas, and then another layer of the remaining chicken mixture.
Drizzle with remaining ¼ cup enchilada sauce; sprinkle with remaining ½ cup of cheese. Cover with foil.
Bake until heated through, about 20-25 minutes. Remove foil and bake for 5-10 more minutes, until cheese is nicely melted on top. Garnish with optional toppings.