Brown the ground beef in a skillet over medium-high heat for 5-7 minutes. Drain excess fat and set aside.

Chop the onion, bell peppers, carrots, and garlic finely. Sauté onion and garlic in the same skillet for 2-3 minutes until translucent.

Add bell peppers and carrots, cooking for another 3-4 minutes.

Transfer browned beef and sautéed vegetables to the slow cooker. Add diced tomatoes, tomato sauce, and beans, stirring gently.

Sprinkle in chili powder, cumin, oregano, salt, and pepper. Mix to combine.

Secure the lid and set slow cooker to LOW for 6-8 hours or HIGH for 3-4 hours.

Check for doneness and adjust cooking time if necessary.

Serve in bowls and top with Greek yogurt, cilantro, and cheese as desired.