chicken enchiladas recipe

1 ½ cups cooked shredded chicken ▢2 cups easy enchilada sauce, divided ▢8 corn or flour tortillas (see note if using flour tortillas) ▢2 ½ cups shredded Mexican-blend cheese, divided ▢salt and black pepper, to taste ▢optional toppings: diced onions, chopped cilantro, sour cream, shredded lettuce, cotija cheese