Green’s Dictionary of Slang

1. the mouth or face.

1772		Covent Garden Mag. Dec. 233/2: Madame de Beaufort’s smooth, white hand, / And pretty pouting nib, Sir, / French Henry brave did use to kiss.
a.1790		C. Dibdin ‘Jack in his Element’ in Collection of Songs II 63: Pray how d’ye like my nib, / My trowsers wide, my trampers rum.
1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1890–1904		Farmer & Henley Sl. and Its Analogues.

2. a die.

1873

J. O’Connor Wanderings of a Vagabond 226: Unveiled from the ruins of Pompeii, were found the skeletons of men around a gaming-table, the dice still ciutched in their skeleton fingers, a speechless evidence that the Pompeians were in the habit of rattling the ‘blarsted nibs’.