Combine graham cracker crumbs, powdered sugar, butter and 1 cup peanut butter in a large bowl, mixing until well blended. Press evenly into the bottom of a 9-inch square pan.
Combine remaining ¼ cup peanut butter and chocolate chips in a microwave-safe bowl. Microwave on High in 30 second intervals, stirring at each interval, until melted and smooth. Spread chocolate mixture over peanut butter layer in pan.
Refrigerate at least 1 hour or overnight. Let stand at room temperature 30 minutes before cutting into squares. Store leftover bars in the refrigerator.
Recipe by The eMeals Blog at http://blog.emeals.com/no-bake-chocolate-peanut-butter-bars/