Green’s Dictionary of Slang

a general epithet of abuse.

1592		Nashe Pierce Pennilesse 20: A malecontent Cutpursse [...] cannot his stabbing dagger, or his nittie loue-locke, keepe him out of the Legend of fanatasticall cockcombs.
1622		Massinger Virgin-Martyr III iii: Sure thy father was some botcher, and thy hungry tongue bit off these shreds of complaints, to patch up the elbows of thy nitty eloquence.
1639		J. Taylor Crabtree Lectures 50: Thou lousie nitty Tayler.
1654		New Brawle 7: [T]hou Villaine, thou nitty Breech’d Knave.
1655		Mercurius Fumigosus 34 17–24 Jan. 268: A one-ey’d Tool-man, called a Taylor, being sore troubled with a Hunting Wife, that would nether let him lick his Thimble, nor winde up his Bottom in quiet, but would follow him open-mouth’d, calling him drunken Roague, Nitty-breech’d Roague.
1659		Greene & Lodge Lady Alimony IV ii: Doth your Mistress take us, you nitty-napty Rascal, for her Bordella’s Blouses?
1699		N. Ward London Spy VII 154: Hold your Tongues you Knitty radish-mongers.
1772		Bridges Burlesque Homer (3rd edn) 71: You nitty, lousy, hump-back’d toad.