Heat oven to 250°F. In ungreased 15x10x1-inch pan, mix pretzels, cereals and nuts.
In small bowl, mix melted butter, brown sugar and Worcestershire sauce until blended. Pour over cereal mixture, stirring to coat.
Bake 1 hour, stirring every 15 minutes. Spread on paper towels; cool about 15 minutes. Store in airtight container.