Preheat your oven to 350°F (175°C).
In a skillet, brown the ground beef over medium heat until fully cooked.
Drain excess fat from the beef.
Add chopped onions and bell peppers to the skillet, cooking until softened.
Stir in the taco seasoning, black beans, and diced tomatoes.
In a large baking dish, layer half of the crushed tortilla chips.
Spoon half of the beef mixture over the chips.
Spread half of the sour cream on top of the beef.
Sprinkle half of the cheddar cheese over the sour cream.
Repeat the layers with the remaining ingredients, finishing with cheese on top.
Bake for 25-30 minutes or until cheese is bubbly and golden.