In a medium saucepan, cook onion and garlic in hot oil over medium heat until onion is tender. Stir in chili sauce, beer, honey, Worcestershire sauce, and mustard. Bring to boiling; reduce heat. Simmer, uncovered, about 20 minutes or until desired consistency, stirring occasionally.
To use, brush chicken with some of the sauce during the last 10 minutes of grilling. If desired, heat any remaining sauce until bubbly and pass with chicken. Makes 12 (2 tablespoon servings).