Preheat the oven to 350°F (175°C).
In a large skillet, brown the ground beef or turkey over medium heat until fully cooked.
Drain excess fat and stir in taco seasoning and salsa.
Add black beans and corn to the meat mixture, stirring to combine.
In a greased casserole dish, layer half of the tortilla triangles at the bottom.
Spread half of the meat mixture over the tortillas.
Sprinkle half of the cheese over the meat layer.
Repeat the layering with the remaining tortillas, meat, and cheese.
Top with dollops of sour cream and any remaining cheese.
Bake in the preheated oven for 25-30 minutes until bubbly and golden.