Preheat oven to 350°F. Line a 9×13 pan with foil and coat generously with nonstick spray and set aside.
In a large bowl combine graham cracker crumbs, chocolate chips, oats, salt, condensed milk and dulce de leche. Stir to combine evenly. Press the mixture evenly into the pan.
Bake for 25-30 minutes until set.
All the bars to cool completely.
Remove the foil from the pan and cut into squares.
Pour the powdered sugar into a bag and place 5-6 squares into the bag. Shake gently to coat with powdered sugar. Remove from the bag, transfer to a platter and repeat with the rest of the squares.
Serve immediately or store airtight for up to 5 days.
