Combine cream cheese, condensed milk, peanut butter, and powdered sugar in a mixer.
Beat on medium speed until smooth and completely combined.
Using a rubber spatula, fold in the Cool Whip and ¾ of the candy until combined.
Pour hot fudge topping into bottom of crust. (If it’s too hard to pour, warm in microwave for a bit to make it pourable).
Pour peanut butter mixture into pie crust. Spread it out.
Drizzle top with chocolate syrup, if desired.
Add chopped candy on top.
Cover and freeze until firm.