Used to describe when something (usually food) is a combination of absolute deliciousness in your mouth and is totes worthy of a "NOM NOM NOM". It can also be used to describe people ("that fuzzy little man peach is nom-alicious)...pretty much anything you want. Also can be spelled "nomalicious," but this way is much cooler.
Chick-Fil-A is nom-alicious. I could eat it every day, nom nom nom.