1.Bring milk to the boil in medium saucepan. Remove from heat. Meanwhile, whisk egg yolks and sugar in medium bowl until combined. Gradually whisk in hot milk.
2.Return eggnog mixture to pan; stir over low heat, without boiling, until mixture is thick enough to coat the back of a spoon. Remove from heat.
3.Add chocolate, brandy and rum; stir until smooth. Beat cream in small bowl with electric mixer until soft peaks form.
4.Pour eggnog into 8 warmed heatproof ¾ cup (180ml) serving glasses; top with cream. Serve sprinkled with nutmeg.