Combine corn syrup and cream in a small saucepan.  Bring to a boil over medium heat.  Remove from heat and add chocolate, stirring until it is melted.  Add vanilla.

Drizzle 1/3 of the chocolate sauce in the bottom of the pie crust.  Sprinkle with 1/4 cup nuts, if desired.  Carefully spread 1 pint of ice cream over the chocolate layer.  Freeze for 1 hour.

Repeat with 1/3 of the chocolate sauce, nuts and remaining ice cream.  Drizzle with remaining chocolate sauce; top with remaining nuts.  Freeze for 2 hours or until firm. 

Serve with whipped cream, if desired.