In a very large microwave-safe bowl, microwave butter on 100% power (high) for 45 seconds or until melted. Stir in the barbecue sauce, Worcestershire sauce, garlic powder and onion powder. Add the cereal, pretzels, crackers, and nuts; stir until evenly coated.
Microwave, uncovered, on 100% power (high) for 5 to 6 minutes or until fragrant and lightly browned, stirring every 2 minutes.
Spread on a large piece of foil to cool. Transfer to storage containers. Store at room temperature up to 2 weeks.