Preheat oven to 180 degrees C. Grease one 20cm square pan.
Combine the 1 cup flour, bicarb soda, oats, brown sugar, salt and melted butter. Mix to combine, mixture will be very crumbly. Press half of the mixture into the bottom of the prepared pan.
Bake for 10 minutes.
Let cool slightly then sprinkle over the crust the chocolate chips and chopped nuts. Mix the caramel ice cream topping with the 3 tablespoons of flour and drizzle over the chocolate chips. Top with the remaining oatmeal mixture. You will need to break it into small pieces to cover.
Bake for 15 minutes. Let bars cool before cutting.