Additional whipped topping, toasted pecan halves and chocolate curls, optional
Place pecans in crust. In a heavy saucepan over medium heat, cook and stir caramels and evaporated milk until caramels are melted and mixture is smooth. Cool for 10 minutes, stirring several times. Pour over pecans; refrigerate.
In a heavy saucepan, combine the milk, marshmallows, chocolate chips and butter; cook and stir over medium heat until marshmallows are melted and mixture is smooth. Remove from the heat; stir in vanilla. Cool to room temperature, stirring several times. Fold in whipped topping. Pour over caramel layer. Cover and refrigerate overnight. Garnish with additional whipped topping, pecans and chocolate curls if desired.