Prep: Line a quarter sheet pan with parchment paper. Peel and slice each banana in half lengthwise, then cut each piece horizontally.
Add Peanut Butter and Nuts: Spread peanut butter evenly over the banana pieces and sprinkle half of the chopped peanuts on top. Freeze for 45 minutes.
Melt Chocolate: Combine chocolate chips and coconut oil in a microwave-safe bowl. Microwave on low in 20-second intervals, stirring until melted.
Assemble Bars: Drizzle half of the melted chocolate over the peanut butter-covered bananas, top with remaining peanuts, and drizzle the rest of the chocolate over the top.
Freeze: Place the bars in the freezer for 2 hours or until set. Transfer the bars to an airtight container and store them in the freezer for up to one month.