1. Preheat oven to 350 degrees.

For the Sauce

1. In a medium pan, melt butter over medium high heat. Whisk in flour to form a paste and cook for about 2 minutes.
2. Gradually whisk in the chicken broth, and bring to a gentle boil, whisking occasionally. When the sauce has thickened slightly, stir in the heavy cream, green chiles, and 1/2 cup of the cheese. Stir until smooth. Remove from heat and set aside.

For the Filling

1. In a large bowl, mix together chicken, black beans, corn, green chiles, cream cheese, and spices.
2. Divide the mixture between eight flour tortillas.
3. Pour enough sauce to cover the bottom of a greased 9 by 13 baking dish. Roll the tortillas around the filling, and place in the pan seam side down.
4. Pour remaining sauce over the filled enchiladas, and sprinkle remaining cheese over the top.
5. Bake for 30 minutes uncovered, or until hot and bubbly and the cheese is beginning to brown. Garnish with avocado, green onions and fresh cilantro.