Preheat your oven to 350°F (175°C).
In a skillet, brown the ground beef over medium heat until fully cooked.
Add the chopped onions and sauté until translucent.
Stir in the taco seasoning, black beans, corn, and diced tomatoes.
Simmer for 5 minutes to blend the flavors.
In a baking dish, layer half of the tortilla strips on the bottom.
Spread half of the beef mixture over the tortillas.
Sprinkle one cup of cheese over the beef layer.
Repeat the layers with the remaining tortillas, beef mixture, and cheese.
Bake in the preheated oven for 25-30 minutes until bubbly and golden.