Cook corn syrup and sugar together in a large pan over medium heat, stirring to dissolve sugar. Bring mixture to a boil. (OR in a 1 quart microwaveable container; microwave on high (100%) for 2 to 2-1/2 minutes until syrup boils). Remove from heat.
Stir in baking soda and vanilla until blended thoroughly. Stir in 1 cup chocolate chips until completely melted and smooth. Add 1 cup M&M candies and cereal and stir to coat completely.
Pour into greased 13x9-inch pan and pat into place.
Top with remaining M&M candies.
Cool and cut into squares. Store in air tight container for up to 2 days.
