Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, cream of chicken soup, sour cream, cheddar cheese, salsa, garlic powder, onion powder, black pepper, and salt. Mix until well combined.
In a greased 9x13-inch baking dish, spread half of the crushed Doritos evenly across the bottom.
Pour the chicken mixture over the Doritos, spreading it out evenly.
Top the chicken mixture with the remaining crushed Doritos.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the top is golden brown.
If desired, sprinkle chopped green onions on top before serving.