Coat bottom and sides of a 8 inch pie plate lightly with butter

Combine chocolate syrup and chocolate chips in a small microwave safe bowl. microwave till melted and smooth. Reserve 1/4 cup

Combine chocolate mixture with cereal in a medium bowl and mix to coat cereal. Press mixture in pie plate and up the sides and freeze for about 15 minutes

Combine remaining chocolate mixture with the sour cream in a small bowl mixing well

Spread half of the ice cream in the pie plate and drizzle with half of the sour cream mixture top with remaining ice cream and spread cool whip on and drizzle with remaining sour cream mixture and drizzle Carmel sauce on and top with nuts if desired and freeze for a couple of hours or longer.