Heat oven to 325°F. Grease and lightly flour 12-cup fluted tube cake pan, or spray with baking spray with flour. In large bowl, beat cake mix, pumpkin pie spice, eggnog, oil and eggs with electric mixer on low speed 30 seconds, then on medium speed 2 minutes. Stir in cranberries and walnuts. Pour into pan.
Bake 45 to 55 minutes or until toothpick inserted near center comes out clean. Cool in pan 10 minutes. Turn cake upside down onto cooling rack; remove pan. Cool completely, about 1 hour.
Melt butter in 2-quart saucepan over medium-high heat. Stir in brown sugar and corn syrup. Heat to boiling. Cook about 1 minute, stirring constantly, until sugar dissolves. Stir in whipping cream. Return to boiling, stirring constantly. Remove from heat. Serve warm sauce over cake.