Preheat oven to 325. Butter and flour 12-cup Bundt pan. Sift flour, baking powder, nutmeg and salt into medium bowl. Beat 1 cup sugar and butter in large bowl until well blended. Add eggs one at a time, beating well after each addition. Beat in vanilla. Reserve 1 tablespoon dry ingredients. Mix remaining dry ingredients into butter mixture alternately with buttermilk in 3 additions, beginning and ending with dry ingredients. Mix dried cranberries with reserved 1 tablespoon dry ingredients in small bowl. Fold dried cranberries into batter.
Transfer batter to prepared pan (batter will come only about halfway up sides of pan). Smooth top. Mix walnuts, cinnamon and remaining 1/4 cup sugar in medium bowl. Sprinkle over batter.
Bake cake until tester inserted near center comes out clean, about 45 minutes. Turn off oven. Open oven door slightly. Let cake stand in oven with door ajar 10 minutes. Turn cake out onto rack; cool completely. (Can be made 1 day ahead. Wrap in foil; store at room temperature.) Sift powdered sugar over cake.
Next time, try fresh cranberries instead of dried, and pecans instead of the walnuts. Use 1/4 cup brown sugar and 1/4 cup white sugar for the topping. Put half the topping mix in the center of the cake, the other half on top so you don't end up with dry cinnamon-sugar mixture left loose on top of the cake.