Mix first two ingredients together and cool. Melt butter and mix into cake mix and 1/3 cup evaporated milk. Pour 1/2 of batter (will be thick) in greased 9x13 inch pan. Bake at 350 degrees for 10 minutes.
Sprinkle nuts and chips over cake. Pour caramel mixture on top and spread remaining cake mix over caramels. Bake at 350 degrees for 20 minutes. Cool and cut into bars.