Place chicken breasts in a large sauce pan and cover with water. Bring to a boil over high heat, then reduce to a simmer. Cook for about 45 minutes until fully cooked and tender.

Remove chicken, transfer to a cutting board, and shred using two forks. Return shredded chicken to the saucepan.

While the chicken simmers, set your oven to HI Broil.

Place Hatch green chiles on a foil-lined baking sheet. Broil for 15 minutes on each side until the skins are charred and blackened.

Transfer the hot chiles to a large bowl and cover with foil to steam for 20 minutes. Once cooled, peel off the skins, remove stems and seeds, then slice into thin strips.

Add cream of chicken soup, milk, and prepared green chile strips to the shredded chicken in the saucepan. Stir over medium-low heat and let it simmer for about 20 minutes until heated through and slightly thickened.

Preheat your oven to 350°F (175°C). Grease a deep rectangular baking pan (approx. 12.7" x 8.9" x 2").

Place 9 corn tortillas in the bottom of the pan in three rows of three. Spread one-third of the chicken-chile filling over the tortillas and sprinkle with cheddar cheese.

Add 6 tortillas (2 in each row), then another layer of the filling and cheese.

Add 6 more tortillas, top with the remaining filling and finish with a generous final layer of cheese.

Bake the enchilada casserole for 30 minutes until bubbly and golden on top. Let cool for 5 minutes before slicing.

Top with chopped tomatoes and shredded lettuce for a burst of freshness and color. Serve hot and enjoy the layers of creamy, spicy goodness.