Place the creamy peanut butter and marshmallow creme in a medium mixing bowl.
Mix until smooth and fully combined. This may be done with a handheld electric mixer or by hand using a sturdy spoon or spatula.
Add the thawed Cool Whip whipped topping to the peanut butter mixture.
Gently fold until the whipped topping is fully incorporated and the mixture is smooth and fluffy.
Add 8 chopped Reese’s Peanut Butter Cups and 1/4 cup mini chocolate chips to the mixture.
Fold gently until the candy and chocolate chips are evenly distributed throughout the fluff.
Transfer the Peanut Butter Fluff to a serving bowl.
Sprinkle the remaining chopped Reese’s Peanut Butter Cups and the remaining mini chocolate chips over the top.
Serve immediately with desired dippers, or cover and refrigerate until ready to serve.