To make the sauce:

1. Heat the oil in a small saucepan over medium-high heat add the tomato sauce and stir in the spices and salt.
2. Whisk in the chicken broth.
3. Make a slurry with the flour and water., then add the slurry to the sauce and whisk well.
4. Lower the heat and simmer for 10 minutes or until the sauce is reduced by about one-quarter and coats the back of a spoon.
5. Remove from the heat and et cool to room temperature.

To make the chicken filling:

1. While the sauce is reducing, prepare the chicken filing: In a large skillet over medium heat, melt the butter.
2. Add the onion and garlic and saute for 2 minutes, until fragrant.
3. Add the chicken, diced green chiles, spices and salt to the skillet and cook for 5 to 7 minutes, until no pink remains in the center of the chicken.
4. Add the spinach and saute for the 1 minute, until wilted. Remove the pan from the heat and set aside.

To make the enchiladas:

1. Mix the two cheeses.
2. Preheat the oven to 375 degrees F. Spoon some of the sauce into the bottom of a 9×13 inch baking dish.
3. Assemble the enchiladas. Spread 1 tablespoon of the enchilada sauce on a tortilla, then place a spoonful or two of the chicken filling in the middle.
4. Drizzle an additional teaspoon or two of the sauce over the chicken, then sprinkle with about a tablespoon of the mixed cheese.
5. Fold the sides of the tortilla up and over the filling and place the tortilla, seam side down, in the baking dish.
6. Repeat with the rest of the tortillas, sauce, filling and cheese.
7. Bake for 15 minutes, or until the edges of the tortillas crisp and the cheese is melted.
8. Garnish with chopped cilantro and diced avocado. Serve immediately.