I just happened to run into a link for this blog post elsewhere tonight...
Word of the Week: Nom...with a note on the actual origin...
The gustatory nom is attributed to the Sesame Street character Cookie Monster (1969-present), who says "Om nom nom nom" while eating omnivorously. In the last couple of years nom has been widely disseminated through the medium of LOLcats; it's defined in a LOLcat Dictionary as "to eat fuds."