Green’s Dictionary of Slang

foolish, dull.

1709		British Apollo No. 8. 3/2: Sometimes Saga as Solon, Oft Nizey as Ben [OED].
1710		British Apollo No. 100. 3/2: Here lies a wretched, Nizey Wight .
1720		C. Shadwell Irish Hospitality I i: Ah Lucy! I am a poor hang-dogly Lover [...] I an’t such a nizey Fool as to die for you; but truly, now my Stomach falls off strangely, I don’t eat so much by a Pound as I used to do.