Step 1: In a large bowl, combine the shredded cooked chicken, 1 cup of the green chile enchilada sauce, 1 cup of the shredded Pepper Jack cheese, 1 cup of the shredded Monterey Jack cheese, diced green chiles, and sour cream. Stir gently until all ingredients are well combined.
Step 2: Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish. Pour approximately 1/2 cup of green chile enchilada sauce into the bottom of the prepared baking dish, spreading it evenly.
Step 3: Warm the tortillas. Wrap a stack of tortillas in a damp paper towel and microwave for 30-60 seconds, or quickly dip each tortilla in the warm enchilada sauce. Optionally, quickly fry each tortilla in a shallow pan with a tiny bit of oil for about 10 seconds per side until pliable.
Step 4: Place about 1/4 to 1/3 cup of the chicken mixture down the center of each warmed tortilla. Roll the tortilla tightly and place it seam-side down in the prepared baking dish. Repeat with the remaining tortillas and filling, arranging them snugly in the dish.
Step 5: Pour the remaining green chile enchilada sauce evenly over the rolled enchiladas. Ensure every enchilada is generously coated.
Step 6: Sprinkle the remaining 1 cup of Pepper Jack cheese and 1 cup of Monterey Jack cheese evenly over the top of the enchiladas.
Step 7: Cover the baking dish loosely with aluminum foil. Bake for 25 minutes, then remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and lightly golden brown. Let the enchiladas rest for 5-10 minutes before serving.
Step 8: Garnish with fresh cilantro and sliced green onions, if desired. Serve immediately. Enjoy your homemade green chile pepper jack chicken enchiladas!