In a large skillet over medium-high heat, brown turkey in fat of choice. Stir in onions, chilies, garlic, oregano, and cumin. Cook, stirring constantly, about 4 minutes.
Mix enchilada and tomato sauces together. Stir queso blanco and 1 cup of the mixed sauce into the meat mixture. Remove from heat.
Butter a 9x13-inch glass baking pan plus a smaller rectangular glass baking dish and place several spoonfuls of sauce in the bottom of each.
Heat the tortillas in a dry cast-iron skillet, one at a time, until they are pliable. Place 1/4 to 1/3 of the filling in the center of each tortilla and top with 2 tablespoons grated cheese. Roll up and place seam-side down over sauce in baking pan. Repeat with tortillas until pans are full. Pour remaining sauce over enchiladas and top with remaining cheese. Sprinkle with sliced olives.
Bake at 350°F for 30 minutes or until cheese is melted and starting to brown.