Nappe: lightly coating a food with sauce. If a sauce nicely coats the back of a spoon, it's said to be "a la nappe": http://www.everything2.com/index.pl?node_id=1510977
Noix: nuts. For example, noix de coco = coconut.
Nouvelle: "new" from "nouvelle cuisine", i.e. the new cuisine, with a new approach to cooking and presentation: http://en.wikipedia.org/wiki/Nouvelle_cuisine