Nunc dimittis - Now let depart
Nunc est bibendum - Now we must drink. (Horace)
Nvdvm pactvm - A nude pact an invalid agreement a contract with illusory benefits or without consideration hence unenforceable

Nvllvm qvod tetiget non ornavit

He touched none he did not adorn - not simply 'the Midas touch', or 'he left things better than he found them', but a tribute to a Renaissance man

Nvnc avt nvnqvam - Now or never
Nvnc dimittis - Now let [thy servant] depart - generally any permission to go, specifically to express one's readiness to depart or die
Nvnc pro tvnc - Now for then retroactive
O curas hominum! O quantum est in rebus inane! - Ah, human cares! Ah, how much futility in the world! (Lucilius)
O di immortales! - Good heavens! (uttered by Cicero on the Senate floor)
O diem praeclarum! - Oh, what a beautiful day!