Preheat oven to 350 degrees.
Melt caramels with 1/3 cup milk in top of double boiler.
Combine cake mix with melted margarine and 1/3 cup of milk.
Spread half of cake mixture into prepared 13x9 inch pan.
Bake for 6 minutes.
Sprinkle chocolate chips and nuts over partially baked layer.
Drizzle melted caramel over all.
Crumble remaining cake mixture over top.
Bake an additional 20 minutes.
Cut into bars when cool.