Crust: Heat oven to 350 degrees. Mix pecans, sugar, and margarine. Press onto bottom and sides of 9 inch pie plate. Bake 12 to 15 minutes or until lightly browned. Cool. Filling: Melt caramels with 1/4 cup milk in heavy saucepan over low heat, stirring frequently until smooth. Pour over crust; sprinkle with pecans. Stir chocolate, 1/3 cup milk, powdered sugar, and vanilla in heavy saucepan over very low heat just until melted. Pour over caramel pecan filling spreading to edges of pie. Refrigerate. Serve with sweetened whipped cream if desired.
