Preheat oven to 325°F. Line 15x10x3/4-inch (38 cm x 25cm x 2 cm) baking pan with parchment paper. (Or grease pan lightly.) Combine cereal, popcorn and nuts in large bowl; set aside.
Place honey, corn syrup and butter in medium saucepan. Bring to boil on medium heat, stirring constantly. Boil 1 min., without stirring. Remove from heat. Stir in vanilla. Drizzle over cereal mixture; toss to coat. Spread into prepared pan.
Bake 20 to 25 min. or until crisp and lightly toasted, stirring after 10 min. Cool completely. Stir to break apart.