1 1/2 cups powdered sugar

Place the chex cereal in a large bowl. Large enough to have enough room to stir things up. Melt the chocolate chips, margarine, and peanut butter in a microwave safe dish, in the microwave for 1 1/2 minutes, or until smooth and creamy when stirred. Add the vanilla, and stir. Pour over the cereal and stir until the cereal is evenly coated. Put the powdered sugar in a large size plastic bag, add the coated cereal and shake until evenly coated with the powdered sugar. Spread over a sheet of waxed paper until cooled off. Store in an air tight container in the refrigerator.