In 4-quart saucepan or Dutch oven, cook onion and garlic in vegetable oil until onion is tender. Add remaining ingredients except chicken. Bring to a boil. Reduce heat to low; cover. Simmer 40 minutes, stirring occasionally. Add cooked chicken; continue simmering 5 to 10 minutes or until chicken is heated through and barley is tender. Add additional water or chicken broth if chili becomes too thick upon standing. Makes about 9 cups.