Dad's Favorite Caramel Oatmeal Bars

1 3/4 cup quick or old fashioned oats
1 3/4 cup flour, divided use
3/4 cup packed brown sugar
1/2 tsp baking soda
1/4 tsp salt (optional)
3/4 cup butter, melted
1 12 oz bag (2 cups) chocolate chips
1 cup chopped nuts
1 cup caramel ice cream topping

Heat oven to 350 degrees. Grease bottom of 13 x 9" metal baking pan. In large bowl, combine oats, 1 1/2 cups flour, sugar, baking soda, and salt. Stir in butter and mix well. Reserve 1 cup of the oat mixture; press remaining oat mixture into the bottom of the baking pan. Bake for 12-15 minutes or until golden brown. Remove from oven and immediately sprinkle with chips and nuts. Mix the caramel topping with the remaining flour in a small bowl then drizzle over the nuts to within 1/4 inch of pan edges. Sprinkle with the reserved oat mixture. Bake for another 18-22 minutes or until golden brown. Cool in pan on wire rack. Refrigerate until firm then cut into bars.