Step 1

Preheat the oven to 350 F.

Step 2

Whisk together the tomato sauce, tomato paste, chicken broth, salt, chili powder, cumin, oregano, and pepper, until smooth.

Step 3

Spread ½ cup enchilada sauce in the bottom of a 3-quart, 9x13 inch pan, then layer 6 tortilla halves over the sauce, until it is fully covered. Layer 2 cups shredded chicken over the tortillas, then pour over 1 cup of enchilada sauce, and 2 cups shredded cheese.

Step 4

Repeat Step 3 to build the next layer, using up the rest of the tortillas, enchilada sauce, and cheese, then bake the casserole at 350 F for 30 minutes, until the top is browned and bubbling. Remove the casserole from the oven and let cool.

Step 5

In a small bowl, whisk together the lime juice and sour cream, then drizzle it over the casserole. Garnish with the avocado and cilantro, then serve!