In small microwavable bowl, microwave baking chips uncovered on Medium (50%) 1 to 2 minutes, stirring after 1 minute, until mixture is smooth. Transfer to small resealable food-storage plastic bag. Cut corner from one end; drizzle over top of cereal mixture. Refrigerate until bar is firm and topping is set, about 20 minutes. Cut into 6 rows by 4 rows.