In a large skillet over medium heat, add the ground beef. Using a spatula, break it up and cook until browned, about 5-7 minutes. Drain any excess fat.
Add the diced bell pepper and onion to the skillet. Cook for an additional 3-4 minutes until the vegetables are softened.
Sprinkle the taco seasoning mix over the beef and vegetables. Stir to combine thoroughly. Add the drained diced tomatoes and corn, mixing well. Cook for another 2-3 minutes until everything is heated through.
While the beef mixture is cooking, warm the taco shells according to package instructions. This usually involves placing them in the oven for a few minutes.
Fill each taco shell with the beef mixture. Top with shredded cheese, a dollop of sour cream, and a sprinkle of fresh cilantro.
