PREHEAT oven to 350° F. Grease a 13 x 9-inch baking pan.
BEAT flour, sugar, butter, baking soda and salt in a large mixing bowl until crumbly. Beat in oats on low speed just until combined. Press half of mixture (about 2 1/2 cups) into bottom of prepared baking pan.
BAKE for 10 minutes. Cool in pan for 2 minutes.
SPRINKLE crust with morsels and nuts. Blend caramel topping with flour. Drizzle over morsels and nuts. Crumble remaining oat mixture over nuts.
BAKE for 18 to 22 minutes or until golden brown. Cool completely in pan on wire rack. Cut into bars.