Preheat oven to 350°F.Line a 9x13 pan with parchment paper.tir together the melted butter, sugar, soda, oatmeal, flour & salt until it's crumbly.Set aside approximately 1 1/4 cups. of the mixture.
Press the remainder of the mixture into the prepared pan, making sure you press firmly. Bake the crust for 10 minutes then remove from the oven.
Stir together the peanut butter and sweetened condensed milk.
Pour and spread the peanut butter filling over the baked crust, making sure to not pull up the crust while you do so.
Spreading in one direction only solves this problem. Combine the reserved crumbs and Reese's Pieces together and spread on top of the condensed milk mixture.
Bake at 350 for another 15 minutes.
Remove from the oven and sprinkle the chocolate chips evenly over the top. Return to oven to bake for another 5-10 minutes or until topping is light golden brown and the chips are melting.