In large microwavable bowl, measure cereals and walnuts; set aside.
In 2-cup microwavable measuring cup, microwave butter until melted, about 30 seconds. Stir in brown sugar and corn syrup; microwave 30 seconds longer or until mixture is boiling. Stir in vanilla and cinnamon. Pour over cereals, stirring until evenly coated.
Microwave uncovered on High about 3 minutes, stirring every minute, until mixture is glazed. Stir in dried bananas. Spread on waxed paper to cool. Store in airtight container.