Preheat oven to 350° F.
Arrange chopped broccoli in a lightly greased 10 x 6 x 2-inch baking dish and set aside.
Melt 1/4 cup butter in a heavy saucepan over low heat; add flour and chicken base, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk; cook over medium heat, stirring constantly, until thickened and bubbly. Pour mixture evenly over broccoli.
Combine water and 3 Tbsp butter in a saucepan; cook over low heat until butter melts. Stir in stuffing mix and chopped walnuts. Spoon mixture on top of sauce. Bake in preheated oven, uncovered, for 30 minutes.
Makes: 6 to 8