Prepare the pan: Line a 9 × 13-inch baking pan with parchment paper, leaving an overhang on two sides. Lightly grease the parchment.
Make the base layer: Combine 1 cup chocolate chips, 1 cup butterscotch chips, and ¾ cup peanut butter in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until smooth, about 1½–2 minutes. Spread evenly in the prepared pan.
Chill the base: Refrigerate or freeze for 15–20 minutes, until completely firm.
Prepare the maple nougat: Melt the butter in a medium saucepan over low heat. Stir in the cook-and-serve pudding mix, powdered sugar, miniature marshmallows, and maple extract. Continue stirring for 3–5 minutes, until the marshmallows melt and the mixture becomes smooth and thick.
Add the nougat: Spread the mixture evenly over the chilled base, working quickly before it begins to set.
Chill the nougat: Refrigerate or freeze for 20–30 minutes, until firm to the touch.
Make the topping: Melt the remaining 1 cup chocolate chips, 1 cup butterscotch chips, and ¾ cup peanut butter in the microwave in 30-second intervals, stirring until smooth. Stir in the roasted, salted peanuts.
Add the topping: Spread the chocolate-peanut mixture evenly over the chilled nougat.
Chill until set: Refrigerate for at least 1 hour, until the top layer is completely firm.
Cut and serve: Lift the slab out using the parchment paper. Let it sit at room temperature for about 10 minutes, then cut into 36 small bars with a sharp knife dipped in hot water and wiped dry between cuts.