Adjust the top oven rack to be positioned in the middle of the oven.
Prepare a springform pan by covering the bottom on the OUTSIDE with foil, up to the middle of the pan. This is don't for the water bath.
Add all the ingredients to a large bowl and stir until well combined.
Press the mixture into a 10 or 10 1/2 inch buttered springform pan. Using a measuring cup, press the crust and try to line the sides about 1 inch up the pan edges. Refrigerate for at least 20 minutes.
Make sure all the ingredients are at room temperature before your begin.
In the bowl of a stand mixer or in a large bowl using a hand mixer, beat the cream cheese until light and fluffy on medium-low speed.
Add the sugar, flour and continue beating until well combined and creamy.
Add the eggs one at a time and beat after each addition until well combined.
Add vanilla extract, eggnog, rum (if using), nutmeg and sour cream and beat well, stopping to scrape the sides and bottom of the bowl.
Optional: Pour cheesecake batter into three different bowls. Mix red gel food coloring into one and green into another, left the third one as is.
Cheesecake Swirl Optional:
Use a 1/4 cup to pour some of the green batter into the center of the cheesecake crust. Use a second 1/4 cup to pour the white/uncolored batter into the middle of the green batter. Use a third 1/4 cup to pour the red batter into the middle of the white batter. The batters will spread, and as you add alternating scoops of batter, they will widen forming concentric circles. Repeat with the remaining batters.
Add the springform pan to a roasting pan, add enough hot water to the roasting pan to come about halfway up the sides of the springform pan.
Bake until the outside of the cheesecake is set, but the center is still slightly loose, about 1 hour 20 minutes.
Try not to open the door of the oven. At the 40 minute mark check on the cheesecake if its done. A small area in the center should wobble slightly and the edges should be puffed and light golden brown.
Turn oven off and prop open oven door and leave the cheesecake to cool in oven for one hour.
Transfer the cheesecake from the roasting pan to a cooling rack.
Run a knife around the edge of the pan and let the cheesecake cool to room temperature, about 2 hours.
Cover and refrigerate at least 8 hours or overnight.
Eggnog Whipped Cream:
Beat cold heavy whipping cream and powdered sugar in a stand mixer with the whisk attachment until soft peaks form. Add eggnog 1 tablespoon at a time, slowly. Continue beating until stiff peaks form. Careful not to over-whip.
Add whipped cream to a piping bag fitted with the star attachment and pipe onto the cheesecake.