1. Preheat oven to 350 degrees.
2. Line a 9×9 pan with parchment paper that sticks up above the sides of the pan. You can use those edges to lift the bars out of the pan when done.
3. Combine oatmeal cookie crumbs and melted butter and press into bottom of pan.
4. Heat Nutella until just pourable. Pour over crust, spreading evenly.
5. Spread chopped oatmeal cream pie pieces in an even layer over Nutella.
6. Pour about 1/2 cup of sweetened condensed milk on top of oatmeal cream pies.
7. Top with white chocolate chips, mini marshmallows, cinnamon chips and butterscotch chips.
8. Pour remaining sweetened condensed milk over the top.
9. Bake for 25 minutes. Bars may still be giggly, just will harden as they cool.
10. Allow bars to cool in pan.
11. Once cool, lift bars from pan and cut into squares.