Preheat oven to 375 degrees and grease a 9 inch pie plate.
Warm the enchilada sauce in a skillet. Once sauce is warm, dip 4 of the tortilla in the sauce to coat and arrange in the bottom of the prepared pie plate.
Then layer 1 cup of the chicken followed by one cup of the cheese over the tortillas in the pie plate. Then sprinkle with 2 Tbsp of the diced green onion.
Dip the remaining tortillas in the sauce and repeat the tortilla, chicken, and cheese layers.
Pour any remaining sauce over the layers.
Bake at 375 for 10-15 minutes until heat through and the cheese is melted.
Cut into 4 slices and serve each slice sprinkle with some of the remaining green onion followed by guacamole if desired.