Seasoning chicken with salt and pepper and then cook chicken in oil until done (5-6 minutes on each side).

Remove chicken, cube it and set aside. 

Put sliced onion into pan and cook them. Add a little oil if needed.

Add 1/2 cup of enchilada sauce and cook until onions are brown and caramelized.

Add chicken into pan and stir.

 Put a layer of enchilada sauce onto the bottom on 9×13 casserole dish

Spoon in the chicken and sauce into tortillas. You can add cheese to the mixture. Roll up tortilla and place seam down into the casserole dish.

Sprinkle cheese and left over enchilada sauce over the tortilla

Bake at 375 degrees for 20-30 minutes.