In a small bowl, sprinkle gelatine over cold water to soften. Heat 1 cup eggnog. Add sugar; stir to dissolve. Add gelatine. Stir until gelatine melts completely. Pour into large bowl. Add remaining eggnog and nutmeg. Chill until slightly thickened, about 1 hour.
Fold in whipped cream. Pour into 8 mold or individual molds. Chill 8 hours or overnight.
For the sauce, drain raspberry juices into small saucepan. Dissolve cornstarch and brandy. Add to saucepan. Cook until thickened. Add raspberries. Chill.
To serve, unmold mousse onto platter. Drizzle with Raspberry Sauce.
