Preheat oven to 350ºF.
Place refried beans in a microwavable bowl, and heat on high for 2 minutes.
After 2 minutes, stir. Heat again for 1 minute. Remove from microwave.
In a 10"-nonstick skillet, add the 1 Tablespoon of vegetable oil and turn to medium-high heat.
Once heated, add chopped onion and saute, stirring occasionally to prevent burning, for about 5-6 minutes.
Add green chilies, salt and pepper. Saute for about 2 minutes more.
Add precooked chicken and heat until warm through, approximately 3 minutes.
Remove from heat. Sit aside.
Assemble your enchiladas.
Place a tortilla on a flat surface.
Spread about a tablespoon of the enchilada sauce down the middle of the tortilla.
Spread about a tablespoon of the re-fried beans on the surface of the tortilla, concentrating mainly down the middle.
Sprinkle some of the chicken/onion mixture on top of the beans. I just used my hands.
Sprinkle 2 tablespoons of the cheese on top of the chicken mixture.
Moving from one side of the tortilla, roll it up into a tube and place in an ovenproof, deep container.
Lay the tortillas in a row, next to each other.
Spread the remaining enchilada sauce over the top of the shells.
Sprinkle with remaining cheese.
Place in the oven and bake for approximately 20 minutes, or until cheese appears bubbly.
Serve with chopped iceberg lettuce and chopped tomatoes.