Combine melted butter, graham crack crumbs, rolled oats, powdered sugar, and 1 cup peanut butter in a large bowl. Mix well. Press dough into a 9x13 inch pan.
In a microwave safe bowl combine chocolate chips and remaining 1/2 cup creamy peanut butter. Microwave on high for 1 minute. Stir. Return to microwave and heat for 20 seconds, stir and repeat process until chocolate is melted and smooth.
Spread melted chocolate/peanut butter over bottom layer in the pan. Allow to cool completely before cutting into bars. (you can allow them to cool at room temperature or in the fridge for quicker results) Store at room temperature in airtight container.
*Oats should be old fashioned rolled oats, not instant oats!