Start by lining a 9x9-inch baking pan with parchment paper, leaving a bit overhanging on the sides.
In a large mixing bowl, combine the melted salted butter, graham cracker crumbs, and powdered sugar. Mix well until smooth.
Stir in the creamy peanut butter until completely combined.
Gently fold in the Rice Krispies cereal until evenly distributed.
Transfer the mixture into the prepared baking pan and press it down firmly and evenly.
In a microwave-safe bowl, combine the chocolate chips and coconut oil. Microwave in 30-second intervals, stirring until melted and smooth.
Pour the melted chocolate over the peanut butter mixture and spread it evenly across the top.
Place the baking pan in the refrigerator for at least 2 hours, or until the chocolate is set.
Once set, lift the bars out of the pan using the parchment paper overhang and cut into squares.