Heat a large skillet over medium-high heat.
Add the ground beef and cook, breaking it apart with a spoon, until browned and cooked through, about 5-7 minutes.
Add the diced onion and minced garlic to the skillet and cook for an additional 2-3 minutes until the onion is softened.
Transfer the cooked beef, onion, and garlic mixture to the crock pot slow cooker.
Add the diced tomatoes, kidney beans, black beans, tomato sauce, and beef broth to the slow cooker.
Stir in the chili powder, ground cumin, smoked paprika, dried oregano, salt, black pepper, and cayenne pepper until well combined.
Cover the slow cooker and cook on low for 6 hours.
After cooking, stir the chili and taste for seasoning, adjusting salt or spices if needed.
Serve hot with your favorite chili toppings if desired.