01 - Preheat oven to 350°F (175°C) and grease a 9x13-inch baking dish.
02 - In a mixing bowl, combine shredded chicken, 1 cup Monterey Jack cheese, 1/2 cup sour cream, green onions, garlic powder, ground cumin, salt, and black pepper until the mixture is evenly blended.
03 - Melt unsalted butter in a saucepan over medium heat. Stir in all-purpose flour and cook, stirring constantly, for 1–2 minutes until the mixture is bubbling but not browned.
04 - Gradually whisk in chicken broth. Continue cooking, whisking frequently, until slightly thickened, about 3 minutes.
05 - Remove saucepan from heat. Whisk in 1 cup sour cream, diced green chilies, onion powder, and remaining salt until the sauce is smooth and fully combined.
06 - Distribute chicken filling evenly onto each flour tortilla. Roll tightly and arrange the tortillas seam-side down in the prepared baking dish.
07 - Pour the white sauce evenly over the rolled tortillas. Sprinkle with the remaining 1 cup Monterey Jack cheese.
08 - Bake uncovered for 25–30 minutes, until the dish is bubbling and the surface is lightly golden.
09 - Allow enchiladas to cool briefly. Garnish with chopped cilantro and extra green onions before serving.