1. Brown the Beef and Onion: In a large Dutch oven or soup pot over medium heat, add the lean ground beef and chopped onion. Cook, breaking up the meat as it browns, until the beef is no longer pink and the onions are softened, about 5-6 minutes.
2. Add Garlic: Stir in the minced garlic and cook for another 2 minutes until fragrant.
3. Add Remaining Ingredients: Pour in the broth, then add the corn, black beans, chili beans (with sauce), crushed tomatoes, chopped green chiles, chili powder, cumin, oregano, onion powder, garlic powder, and season with salt, pepper, and a pinch of cayenne. Stir until well combined.
4. Simmer the Soup: Cover the pot with a lid and let the soup simmer on low heat for 15 minutes, stirring occasionally to prevent sticking and allow flavors to meld. You can simmer longer if desired for a thicker texture.
5. Serve and Top: Ladle the hot taco soup into bowls and top with your choice of shredded cheese, sour cream, diced avocado, green onions, tortilla chips, or fresh cilantro.

Slow Cooker Option:

1. Combine Ingredients: Place raw ground beef in the bottom of a slow cooker and carefully break into small chunks with a spoon. (Optionally, brown it first on the stovetop for extra flavor.) Add all other soup ingredients to the crockpot and stir gently to combine.
2. Cook: Cover with a lid and cook on high for 4-6 hours or on low for 8-10 hours, until the flavors are fully developed and the beef is tender.
3. Finish and Serve: Stir well, taste and adjust seasoning if needed, then serve hot with your favorite toppings.