Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded chicken, sour cream, cream of chicken soup, 1 cup of shredded Monterey Jack cheese, garlic powder, onion powder, cumin, salt, and black pepper. Mix well until all ingredients are evenly combined.
Warm the flour tortillas in the microwave for about 30 seconds to make them pliable.
Spoon about 1/4 cup of the chicken mixture onto each tortilla, sprinkle with some diced green chilies, and roll them up tightly. Place the rolled tortillas seam-side down in a greased 9x13 inch baking dish.
In a separate bowl, whisk together the milk and the remaining chicken mixture. Pour this mixture evenly over the rolled enchiladas in the baking dish.
Sprinkle the remaining 1/2 cup of shredded Monterey Jack cheese on top of the enchiladas.
Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let cool for a few minutes. Garnish with fresh cilantro if desired before serving.