Heat oven to 350°F. Spray 9-inch glass pie plate with cooking spray. In medium bowl, mix pretzels, brown sugar and butter; firmly press mixture on bottom, up side and onto rim of pie plate. Bake 10 to 12 minutes or until lightly browned. Cool completely on cooling rack. Reduce oven temperature to 325°F. In medium bowl, beat cream cheese and granulated sugar with electric mixer on medium speed until blended. Add sour cream and peanut butter, beating on low speed until well blended. Add eggs, one at a time, beating just until blended. Arrange 1 cup candy pieces in bottom of crust. Spoon cream cheese mixture over candy. Bake 35 to 40 minutes or until set. Cool completely. Cover; refrigerate 2 hours.
Microwave chocolate chips and whipping cream on High 30 seconds or until melted and smooth. Drizzle chocolate sauce over pie; sprinkle with peanuts and remaining candy pieces.