NATO
naval, navel
Your navel is your umbilicus, or belly button in common parlance. Naval means “of the navy”, like a naval officer.
Nestlé
Netherlands, the
Not Holland. Strictly speaking, Holland refers to just the two provinces of North and South Holland, not the whole of the Netherlands.
never mind
Two words (unless it’s part of the obsolete expression “pay something no nevermind”).
non
There’s no such word as non on its own, except in established (Latin) phrases such as persona non grata. It can usually only be part of a compound: without a hyphen (as in nonentity) or with a hyphen (as in non-executive).
no one
Two words, no hyphen.
Nordic countries
Norway, Sweden, Denmark, Iceland and Finland and associated territories. See also Scandinavia.
north
See compass points.
northeast
See compass points.
northwest
See compass points.
not
Some writers seem to feel an urge to emphasise the word “not” in bold or caps, lest the reader fail to spot it, presumably – as in “Abusive or aggressive behaviour towards our staff will NOT be tolerated” or “Applications received after the deadline will NOT be considered”. I can assure you, it’s not necessary. (See what I did there?)