Heat oven to 450°F. Unfold crust and fit into ungreased 9-inch pie plate. Flute crust edge. Prick bottom and sides with fork. Line crust with foil; fill with pie weights or uncooked beans.
Bake in 450°F oven for 5 minutes. Remove foil and beans. Bake until crust is lightly golden, about 5 minutes more. Set aside.
In medium-size microwave-safe bowl, combine 1/2 cup heavy cream and 1-1/2 cups chocolate chips. Microwave on high 1 minute; stir until smooth. If necessary, microwave in 15-second intervals until completely melted. Spread over bottom of pie. Refrigerate while preparing topping.
In large bowl, stir together cereal, pecans and coconut. In medium-size saucepan, stir together remaining 3/4 cup heavy cream, the corn syrup and brown sugar. Bring to boiling over medium heat; boil until mixture registers 240°F, soft ball stage, on candy thermometer, about 20 minutes.
Quickly pour caramel mixture over cereal-nut mixture; stir until completely coated. Spoon evenly into piecrust, mounding slightly in center.
Place remaining 1/2 cup chocolate chips into small microwave-safe bowl. Microwave on high until melted, about 1 minute; stir until smooth.
Place melted chocolate into small plastic food-storage bag snip off one small corner. Drizzle chocolate over pie. Refrigerate overnight. Serve with whipped cream, if desired.
