PREHEAT oven to 350° F. Grease 13 x 9-inch baking pan.
MICROWAVE sugar, butter and water in large, microwave-safe bowl on HIGH (100%) power for 3 minutes until mixture boils, stirring once. Add chocolate; stir until melted. Stir in eggs, one at a time, until incorporated. Stir in vanilla extract. Add flour, baking soda and salt; stir well. Stir in nuts. Pour into prepared baking pan.
BAKE for 16 to 20 minutes until wooden pick inserted in center comes out still slightly sticky. Cool in pan on wire rack. Cut into bars.