In microwave, melt ½ pkg chocolate chips, ½ stick margarine, ½ cup peanut butter for 1 minute. Stir, then cook for 20-30 seconds. Stir. In a large bowl, pour ½ box Rice Chex. Pour chocolate mixture on top and stir until well coated. Pour ½ box powdered sugar in bottom of paper bag. Dump chex mix on top. Shake and shake until well coated. As you can see I halved the recipe because mixing all once is a pain.