PREHEAT oven to 325º F. Grease 8-inch-square baking pan. Set aside 1/3 cup morsels.
HEAT 1 1/3 cups morsels, sugar, butter and water in small saucepan over low heat, stirring constantly, until chocolate and butter are melted. Pour into medium bowl. Stir in eggs, one at a time, with wire whisk until blended. Stir in vanilla extract. Add flour and salt; stir well. Stir in remaining 1/3 cup morsels and nuts. Pour into prepared baking pan.
BAKE for 38 to 40 minutes or until wooden pick inserted in center comes out slightly sticky. Cool in pan on wire rack. Cut into bars.