In a large skillet, heat the olive oil over medium heat. Add the diced onion and bell pepper, cooking until softened, about 5 minutes.
Add the minced garlic and ground beef to the skillet. Cook until the beef is browned and cooked through, breaking it apart with a spatula, about 6-8 minutes. Drain excess fat if necessary.
Stir in the taco seasoning, diced tomatoes, corn, and black beans. Mix well and let simmer for about 5 minutes, allowing the flavors to meld. Season with salt and pepper to taste.
Sprinkle the shredded cheddar cheese over the top of the mixture. Cover the skillet and let it cook for an additional 2-3 minutes, or until the cheese is melted.
Remove from heat and top with crushed tortilla chips. Garnish with fresh cilantro if desired. Serve with sour cream on the side.