Preheat oven to 350°. Combine first 3 ingredients; stir in oatmeal and ½ cup walnuts. Pat mixture into a greased 9 x 13 pan. Bake 15-18 minutes. Remove from oven and place cut marshmallows, with the cut side down on top of bars, spacing 6 on the long side and 4 across making a total of 24. You will cut these bars later so this makes a good cutting guide. Sprinkle on the white and butterscotch chips, coconut and walnuts. Return to oven for 5 minutes. Remove from oven and drizzle with Creamy Caramel Sauce.
TIP: Keeping the marshmallows in approximately ½ inch from the edges of the pan will make cutting them easier.