Heat oven to 450. Prepare pie crust according to pkg. directions for one crust baked shell using 9 inch pie pan. Bake for 9-11 minutes or until light golden brown. Cool completely.
In small saucepan over low heat, melt 1/2 cup chocolate chips and 1 T. butter with 2 t. water, stirring constantly until smooth. Blend in powdered sugar until smooth. Add additional water if necessary for desired spreading consistency. Spread mixture over bottom and up sides of cooled baked shell. Refrigerate.
In medium saucepan, combine 1 cup butter and brown sugar. Cook over medium heat until butter is melted and mixture is smooth, stirring frequently. Refrigerate 10 minutes. In large bowl, beat peanut butter and brown sugar mixture at low speed until blended. Beat 1 minute at medium-high speed. Add 12 oz. whipped topping; beat 1 additional minute at low speed or until mixture is smooth and creamy. Pour over chocolate layer. Refrigerate.
In small saucepan over low heat, melt 1/2 cup chocolate chips and 1 T. butter with 2 t. milk and cornsyrup, stirring constantly until smooth. Add additional milk if necessary for desired spreading consistency.
Spoon and gently spread topping mixture evenly over filling. Refrigerate at least 2 hours to set topping. Garnish with whipped topping and peanuts.