In a large pot or Dutch oven, brown the ground beef (or turkey) over medium heat until fully cooked. Drain excess fat if necessary.
Add the diced onion, bell pepper, and minced garlic to the pot. Sauté for about 5 minutes, or until the vegetables are softened.
Stir in the black beans, kidney beans, corn, diced tomatoes, taco seasoning, and beef broth. Mix well to combine.
Bring the mixture to a boil, then reduce the heat to low. Simmer uncovered for about 20-25 minutes, stirring occasionally.
Taste and season with salt and pepper as needed.
Serve hot, topped with shredded cheddar cheese, a dollop of sour cream, and tortilla chips on the side.