In large mixing bowl, combine flour (2 c.), oats, brown sugar, baking soda, salt, and melted butter.
Blend at low speed to form crumbs.
Press 1/2 mixture into bottom of 9x13 pan.
Bake at 350 degrees 10-12 minutes.
Remove from oven.
Sprinkle with chocolate chips and nuts.
Blend together caramel topping and 6 Tbsp flour.
Drizzle on top.
Sprinkle with reserved crumbs.
Return to oven for 15-20 minutes, until golden brown.
Chill several hours.
Cut into bars.
Serve with caramel ice cream and topping.