Preheat oven to 350 degrees F. Grease a 13 x 9-inch pan.
Combine oats, flours, potato starch, xanthan gum, sugar, butter, baking soda and salt in large bowl; cut the butter into the oat mixture until it is well blended. Reserve 3 cups. Press remaining mixture into bottom of prepared pan.
Bake 10 minutes or until light brown.
Sprinkle chocolate chips over baked crust. Place pan back in the oven for 1 minute to melt the chocolate chips. Gently spread the chocolate with a spatula.
Sprinkle nuts over chocolate chips.
Drizzle caramel over chocolate chips and nuts, but try not to let the caramel touch pan edges. Sprinkle with reserved oat mixture.
Return to oven. Bake 20 minutes or until golden brown. Place pan on cooling rack to cool. Cool completely before cutting.
Recipe by Premeditated Leftovers™ at https://premeditatedleftovers.com/?p=15435