Add shredded rotisserie chicken to a large bowl. Pour just under half of the enchilada sauce over the chicken and stir to coat. Reserve remaining sauce for dipping. Let sit 2 to 3 minutes.

Heat a large skillet over medium heat. Add 1 teaspoon butter if using and let it melt.

Place one tortilla in the skillet. Sprinkle 1/4 to 1/2 cup shredded cheddar evenly over the surface.

Spoon a generous layer of enchilada chicken over the cheese and spread evenly. Add chopped cilantro if desired. Top with another 1/4 to 1/2 cup cheddar.

Place a second tortilla on top and press gently. Cook for 2 to 3 minutes until the bottom is golden brown and crispy.

Flip carefully with a wide spatula and cook the other side for 2 more minutes until golden and cheese is fully melted.

Transfer to a cutting board and slice into wedges. Repeat with remaining ingredients. Warm reserved enchilada sauce and serve alongside with avocado slices and cilantro.