1943 May 8, “Jive”, in The Billboard, Nielsen Business Media, Inc., ISSN0006-2510, page 58:
The story builds up to a jitterbug contest to last for 10 nickel notes on the magnificent juke box, which is also called the “organ.”
Noun: a bill, coin or other form of money worth five cents
1947 May 24, “Record Reviews”, in The Billboard, Nielsen Business Media, Inc., page 124:
Travelling Blues may bring in some nickel notes where the gal enjoys a following.
Kregg P. Jorgenson (2001) Very Crazy, G.I.!: Strange but True Stories of the Vietnam War, page 116: ““Numbah one, Mamma-san! Good job!” a specialist four said, handing the hootch maid a five-cent military payment certificate as a tip. While the nickel note might be enough for a G.I. to buy a can of beer, it was still only five cents.”
1988, Insights, volume 2, Prentice Hall Law & Business, page 32:
1. Inco Limited (Company), a Canadian corporation and major producer of nickel, copper, precious metals, and cobalt, is registering Variable Rate Subordinated Debentures or “Nickel Notes”. According to the terms of the subscription offer, the Company is issuing to its holders of Common Stock the Rights to subscribe for $500 worth of Nickel Notes dependent upon the number of Rights held...
Canadian Tax Foundation (1993) Corporate Management Tax Conference: “...such as the proposed issue of Nickel Notes (debt with part of the return thereon tinked to the price of nickel) by Inco Ltd. in 1988”