01 - Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish.
02 - In a bowl, mix shredded chicken, 1 cup Monterey Jack cheese, 1/2 cup sour cream, green onions, garlic powder, cumin, salt, and pepper until combined.
03 - Melt butter in a saucepan over medium heat. Stir in flour and cook for 1-2 minutes until bubbling but not browned.
04 - Slowly whisk in chicken broth. Cook, stirring, until slightly thickened, about 3 minutes. Remove from heat and whisk in sour cream, green chilies, onion powder, and salt until smooth.
05 - Divide the chicken mixture evenly among tortillas, roll up, and arrange seam-side down in the prepared dish.
06 - Pour the white sauce evenly over enchiladas. Sprinkle with remaining cheese.
07 - Bake uncovered for 25-30 minutes, until bubbly and lightly golden.
08 - Let cool briefly. Garnish with cilantro and extra green onions before serving.