Ladle 1 cup of sauce into the bottom a 9 x 13 baking pan. Set aside.
Pour 1 cup of sauce into a low shallow pie plate or bowl.
Using tongs, dip a tortilla into the sauce to coat one side. Flip over and coat the other side. Allow the excess to drip off. Place on a work surface or plate.
Layer ¼ cup of chicken into the tortilla. Top with cheese and some green onions. Roll to close and place in baking pan. Repeat with remaining tortillas.
If making ahead of time, spoon a little more sauce over the enchiladas and cover the whole pan with plastic wrap. Refrigerate until before baking time.
When ready to bake, add extra sauce if they enchildas look like they need it. Sprinkle the reserved cheese on top.
Bake for 30 minutes until the cheese is melted and golden.
See notes below for serving suggestions.