Preheat the oven to 375 degrees. Grease a 6 x 9 inch casserole pan.
On the bottom of the pan, spread about ½ cup of the sauce and top with 2 of the corn tortillas.
Mix the cooked turkey with the chopped spinach and ½ cup of sauce and spread on top of the corn tortillas. Lay 2 more corn tortillas over the mixture. Combine the corn with the black beans and ½ cup of sauce and spread over the corn tortillas.
Add the last 2 corn tortillas to the top, spread the remainder of the sauce over these and top with the shredded cheddar cheese.
Bake in oven until bubbly and hot, about 35 – 40 minutes. Let rest about 5 minutes before cutting and serving.
Top with sour cream and guacamole. Makes six servings.