Preheat oven to 350 degrees. Lightly oil a 9x9-inch baking dish; set aside. In a large nonstick skillet, over medium-high heat, heat 1-1/2 Tbsp. oil. Add ground chicken, onion, green chilies, salt and pepper. Saute about 10 minutes, until meat is no longer pink. Spoon a thin layer of enchilada sauce in the bottom of pan. Add a layer of 4 overlapping tortillas. Spoon one third of meat mixture over tortillas. Drizzle with enchilada sauce and sprinkle with 1/2 cup cheese. Continue to layer in this manner until all ingredients are used, ending with a layer of cheese. Bake for 15 to 20 minutes until hot and bubbly. Cut into squares. If desired, top each serving with a dollop of sour cream and a sprinkling of cilantro.