1. adjust oven rack to middle position and heat oven to 400 degrees. Heat oil in large saucepan over medium high heat until shimmering . Cook onion unitl softened, about five minutes. Add chili powder and cumin and and cook unitl fragrant about thirty seconds. Stir in tomato sauce, broth, and salt and simmer until slightly thickened about five minutes. Cover and keep warm.
2. Toss Chicken, 1/4 cup sauce, 1 cup cheese, and cilantro in bowl. Spread 1/2 cup sauce tortillas on plate and microwave until pliable about one minute. Place four tortillas on bottom of dish and cover with half chicken mixture. Top with four tortillas and and half of remaining sauce. Cover with remaining chicken mixture, tortillas, sauce and cheese.
3. Wrap with foil and bake until heated through, about 15 minutes. Remove foil and bake until cheese is light browned, about five minutes.