Heat the large pot or Dutch oven over medium heat. Add the ground beef and cook until browned, breaking it apart with a wooden spoon. Drain any excess fat.
Add the diced onion and bell pepper to the pot. Sauté for about 5 minutes until the vegetables are soft.
Stir in the minced garlic and cook for 30 seconds until fragrant.
Add the black beans, kidney beans, corn, diced tomatoes, taco seasoning, broth, and water. Stir to combine.
Increase the heat to bring the mixture to a boil. Once boiling, reduce heat to low and let simmer for about 30 minutes to meld the flavors, stirring occasionally.
Taste and season with salt and pepper as needed.
Serve hot, garnished with optional toppings like shredded cheese, sour cream, chopped cilantro, and tortilla chips.