Heat the olive oil in a skillet over medium heat. Add the lean ground beef and cook until browned, breaking it up with a spoon as it cooks.
Transfer the browned beef to the slow cooker.
Add the sweet potatoes, onion, garlic, diced tomatoes, black beans, chili powder, cumin, salt, black pepper, and beef broth to the slow cooker.
Stir everything together until evenly combined.
Cover and cook on low for 6 to 7 hours, or until the sweet potatoes are tender.
Ladle into bowls and top each serving with chopped fresh cilantro.