For the Eggnog Ice Cream:

1. Whip heavy cream until stiff peaks form. Set aside.
2. In a large bowl, whisk together condensed milk, eggnog, nutmeg, and salt.
3. Fold in the whipped cream until well combined. Transfer to a freezer container and chill for several hours until the ice cream has set.

For the Sweet Whiskey Sauce:

1. In a small saucepan bring the cream to a gentle simmer.
2. Stir the water and cornstarch together and add to the cream, whisking all the while.
3. Bring to another slow simmer and continue to whisking.
4. Remove the pot from the heat and stir in the sugar and whiskey.
5. Stir until the sugar is completely dissolved.
6. Let cool and use over ice cream or pudding.