To prepare the tortillas: Heat a nonstick skillet on medium-high heat. Lightly spray with cooking spray and add a tortilla or two, depending on the size of the pan. Spray the top side of the tortilla lightly with cooking spray. Lightly toast the tortillas, flipping once. Set aside.
In a 13x9-in baking dish, spread ½ cup salsa verde. Layer 6 tortillas to cover the bottom of the dish, overlapping a bit and going up the sides.
Layer half the chicken, 1 cup salsa, and 1 cup cheese. Repeat layering 6 tortillas, the remaining chicken, 1 cup salsa, and 1 cup cheese. Top with the remaining tortillas, salsa, and cheese.
Cover baking dish with foil. Bake at 350°F for 20-25 minutes until heated through and all the cheese is melty. Serve topped with a dollop of sour cream and fresh cilantro.
Calorie count is purely an estimate calculated using an online application to serve as a guide and not to be taken as accurate nutritional information. Percent Daily Values are based on a 2,000 calorie diet.