Cook ground beef and Italian sausage in a skillet over medium-high heat until brown, 5 to 10 minutes. Drain grease and put meat into slow cooker.
Cook bell pepper, onion, and garlic in the skillet until onion is softened and slightly brown, about 5 minutes. Add to slow cooker. Season with garlic, chili powder, salt, cumin, black pepper, oregano, and Greek seasoning. Pour in tomatoes, tomato sauce, kidney beans, and black beans. Stir well.
Cook on Low for about 6 hours, stirring occasionally. Serve over chips and top with toppings of your choice.
