In a large skillet, cook beef and onion over medium heat until meat is no longer pink; drain. Transfer to a 5- or 6-qt. slow cooker. Stir in the beans, corn, tomatoes, juice, salad dressing mix and taco seasoning.
Cover and cook on high for 4-6 hours or until heated through. Serve with sour cream, cheese and corn chips if desired.
Freeze Option: Freeze cooled chili in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally and adding a little broth or water if necessary.