Green’s Dictionary of Slang

(UK Und.) the object in question; the ‘game’.

1864, 1867, 1870		Hotten Sl. Dict. 190: Nux the ‘plant,’ or object in view; ‘stoll up to the NUX?’ ‘Do you fully comprehend what is wanted?’ ― North Country Cant.
1881		Newcastle Courant 9 Sept. 6/5: Now Dandy, you stoll up to the nux, I suppose.