In separate bowl, combine cake mix, butter, and evaporated milk. Do NOT mix the chocolate chips into mixture.
Put half of cake mixture in a greased & floured 9x13 pan. Bake 6 minutes at 350 degrees. Sprinkle chocolate chips over cake mixture (DO NOT MIX INTO CAKE BATTER). Pour caramel mixture over chocolate chips. Pour remaining cake mix on top, dropping mix by spoonfuls.
Bake at 350 degrees for 18 minutes, cool 20 minutes, cut into bars.