In a large pot or Dutch oven, brown the ground beef over medium heat until fully cooked. Drain excess fat.
Add the diced onion and minced garlic to the pot and cook until the onion is translucent.
Stir in the black beans, kidney beans, corn, diced tomatoes, tomato sauce, and beef broth.
Add the taco seasoning, chilli powder, salt, and pepper. Stir to combine.
Bring the soup to a boil, then reduce the heat and let it simmer for 20-30 minutes to allow the flavours to meld together.
Serve hot, garnished with your favourite toppings like shredded cheese, sour cream, sliced jalapeños, or chopped cilantro.