Green’s Dictionary of Slang

1. a martinet, a disciplinarian.

1977		J. Sayles Union Dues (1978) 42: Now this Budka is notorious, worst accident record in the mine and pictures himself as a real nutcracker. Always on your back for chickenshit.
1981		Graziano & Corsel Somebody Down Here Likes Me, Too 38: Even the gym starts to become a lotta fun. There’s all kinds of nutcrackers there.
1992		Herman’s Head [Fox-TV] When Tchaikovsky wrote ‘The Nutcracker’ he had her in mind [HDAS].
2001		J. Stahl Plainclothes Naked (2002) 219: Nut-cruncher [...] Eva Marie Saint was the same way. Used to tease Marlon somethin’ awful.

2. (US) something difficult, impossible or dangerous.

1948		E. Hemingway letter 15 Dec. in Baker Sel. Letters (1981) 656: Just because something was sold for a miserable price once when my nuts were in the nut-cracker after 1944 is no reason to sell something else for a miserable price.
1959		‘Ed McBain’ Killer’s Wedge (1981) 25: Four intelligent men with a nut cruncher of a problem.
1960		J. Carpenter Youngest Harlot 128: I was a ham-and-egger when I sailed on that nutcracker [HDAS].
1978		T.H. White In Search of Hist. 44: History I had the reputation of being a nut-cracker.