Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking pan.
In a large bowl, cream together the butter and sugar until light and fluffy. Mix in water and egg, then stir in cake mix. Finally, mix in nuts and chocolate chips. Spread mixture into pan.
Bake for 30 to 35 minutes in the preheated oven. Cool completely before cutting into bars.
