3. Step
Combine enchilada sauce, sour cream and chipotles to taste in a small bowl. Spread 1/2 cup of the mixture in the pan. Place 4 tortillas over the sauce, overlapping them to cover the bottom. Top with half the chicken mixture, 1/4 cup onion and 1/2 cup cheese. Layer on half the remaining sauce, 4 tortillas, the remaining chicken, 1/4 cup onion and 1/2 cup cheese. Top with the remaining tortillas, sauce and cheese.