Line a cookie sheet with parchment paper and set aside.
Add the softened cream cheese, powdered sugar, cinnamon, nutmeg and rum extract to a medium mixing bowl. With an electric mixer, mix on medium speed until completely blended and smooth. Set aside.
Add 2/3 cup of the white chocolate melts and the eggnog to a microwave safe bowl. Microwave at 50% power for one minute. Remove from microwave and stir until completely melted and smooth. Since all microwave wattages are different, you may have to microwave for an additional 20-30 seconds until the chocolate is completely melted. Fold the melted chocolate into the cream cheese mixture.
Place bowl in freezer for 15 minutes for easier handling.
Roll the truffle dough into 1 inch balls and place on the parchment lined cookie sheet. Place in refrigerator for 15 minutes to allow to harden. (Rolling the dough into balls with your hands will soften the dough quite a bit).
Melt the remaining white chocolate melts in the microwave at 50% power for one minute (or more, if needed). Remove from microwave and stir until completely melted.
Dip each truffle ball into the melted white chocolate and place back on the lined cookie sheet. Immediately, sprinkle ground nutmeg on top of each eggnog truffle.
Chill for 30 minutes to allow the white chocolate coating to completely harden.
Store in an airtight container in the refrigerator (for up to 2 weeks) or the freezer (for up to 2 months).