Optional: Cook onion over medium heat until soft, about 5 minutes. Stir in cayenne, chili powder, paprika, and cumin, cook for 30 seconds to 1 minute. Add ground meat and garlic, cooking to brown the meat. Transfer browned meat mixture to the slow cooker.
Add the remaining ingredients, except the macaroni, to the slow cooker. Add any desired salt and pepper then cover and cook on low 6 hours.
When ready to serve, cook the macaroni per package instructions, then drain and stir into the chili. Serve, garnished with shredded cheese, sour cream, fresh chopped peppers or green onions, and enjoy!