Heat the olive oil in a large skillet over medium-high heat and add the ground beef.
Cook the beef until browned, breaking it into small crumbles with a spatula, then drain any excess fat.
Transfer the browned beef into the slow cooker insert.
Add the finely chopped yellow onion, diced red bell pepper, and minced garlic to the slow cooker.
Stir in the kidney beans, diced tomatoes, tomato paste, and beef bone broth.
Add the chili powder, cumin, sea salt, and black pepper, stirring well to ensure the spices are evenly distributed.
Cover and cook on low for 6 to 8 hours or on high for 3 to 4 hours until the vegetables are tender and the flavors have melded.
Stir once more before serving hot in a deep bowl.