Heat a large skillet over medium-high heat.
Add ground beef and cook, breaking it into irregular crumbles.
Add diced onion once the beef is partially browned.
Continue cooking until the beef is fully cooked and the onion begins to soften.
Add garlic and cook for approximately 30 seconds.
Drain excess grease if necessary.
Transfer the beef mixture to a 6-quart slow cooker.
Add black beans, pinto beans, corn, diced tomatoes with their juices, tomatoes with green chiles, and tomato sauce.
Add taco seasoning, chili powder, cumin, smoked paprika, and black pepper.
Pour in the beef broth and stir.
Cover and cook on LOW for 6–7 hours or HIGH for 3–4 hours.
Stir and adjust the consistency with additional broth if desired.
Stir in fresh lime juice.
Taste and adjust salt and seasonings.
Let rest uncovered for approximately 5 minutes.
Ladle into bowls.
Serve with your favorite taco toppings.