Line a 9 x 9-inch cake pan with aluminum foil and set aside.
Spray the sides of a large saucepan with butter-flavor non-stick spray.
Add the eggnog and sugar, and bring to a rolling boil over medium to medium-high heat, stirring constantly
Boil for two full minutes.
Fold in the marshmallows, cinnamon, and nutmeg.
Bring back to a rolling boil for another 6 minutes, stirring constantly. The mixture will start to turn brown, which is normal, but if you see brown flakes in the mixture then turn down the heat a little.
Remove from heat and add the butter, chips, and nuts.
Stir until thoroughly mixed or until the mixture starts to lose its glossy appearance.
Pour into prepared pan.
Cool at room temperature.
Remove from pan, remove foil, cut into 1-inch squares.