Pre-heat the oven to 160°C and grease an 8 inch square baking tin.
Whisk the sweet rice flour and tapioca flour together until combined.
Add the oats, hazelnuts, butter, sugar, baking powder and salt and rub together with your hands until everything has come together to form a light dough.
Press ½ the dough into the base of the baking tin to form an even layer.
Melt the chocolate, hazelnut butter, cocoa powder and evaporated milk together in a double boiler, mixing together until thoroughly combined.
Spread the ‘nutella’ chocolate mixture on top of the first layer of dough.
Add the chocolate chips to the rest of the dough then crumble the dough on the top and press down lightly into the chocolate, don’t worry too much about it spreading out evenly.
Bake in the oven for 35 minutes until the top is golden brown.
Remove from the oven and leave to cool for an hour or so before removing from the tin. Leave to cool completely on a wire rack before cutting into bars.