The best replacement for nutmeg is mace.

The best alternatives to nutmeg are rated as following:
★★★★★  mace
★★★★★  cinnamon
★★★★  allspice
★★  cloves
★  ginger
★  ground nutmeg
★  cinnamon rice pudding
★  fresh grated nutmeg
  fresh nutmeg
  dry nutmeg

Your alternative for nutmeg is not listed? Suggest!
Speaking about nutmeg, one probably shouldn't forget about eggnog.

Other search terms related to nutmeg and their ratings are:

★★★★★ eggnog
You have in mind a companion for nutmeg and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of nutmeg in all years. Click on graph for more.