Recipe(tried): Betsy, here is the Choc. Swirl Eggnog Pie, from the Dec. 1978 (gosh 20 years ago)

CHOCOLATE SWIRL EGGNOG PIE

MAKE THIS PIE A DAY AHEAD SO IT HAS PLENTY OF TIME TO CHILL BEFORE SERVING.

CHOCOLATE CRUST (RECIPE FOLLOWS)
1 envelope unflavored gelatin
1/4 cup cold water
2 tbls cornstarch
1/2 cup sugar
2 cups eggnog
1 1/2 oz. semisweet chocolate, melted
1 cup heavy cream, whipped
6 tbls rum or 3/4 tsp rum extract
semisweet chocolate curls

Prepare crust; cool. Sprinkle gelatin over water; set aside. Mix cornstarch, sugar, and eggnog. Cook over medium heat, stirring until thickened; stir in the gelatin. divide mixture in half and add chocolate to one portion. Chill both until they mound.
Fold whipped cream and rum nto white portion, then spoon nto crust. Top with chocolate portion and then swirl chocolate through cream layer, Chill well: top with choclate curls.
chocolate crust. Mix 1 cup all-purpose flour, 1/4 cup packed brown sugar, 3/4 cup chopped nuts,, and o ounce semisweet chocolate (grated). Add 1/3 cup melted butter or margarine; press into a 9 inch pie pan. Bake in a 375 degree oven for 15 minutes.
I haven't tried it but I would think you could use cool-whip in place of whipping cream. Just not sure.