Combine first 3 ingredients in a medium bowl. Coat cereal mixture evenly with cooking spray. Transfer to an aluminum foil-lined jelly-roll pan coated with cooking spray.

Bake at 350° for 7 minutes. Stir mixture, and coat evenly with cooking spray. Bake 7 more minutes. Stir in nuts and raisins. Cool. Store mixture in an airtight container.