When a to-be-coin is cut out of the metal strip by the blanking press, that creates...
a blank, also called type 1.
The blank goes through an upsetting mill which uses pressure to create a proto-rim that creates...
a planchet, also called type 2.
The planchet is struck to create a coin.
Occasionally, blanks and planchets escape the mint without being struck (the mint has also given out cent planchets as tour souveniers and included them in mint sets to fill an empty spot).
What you are seeing is the raw surface that should have been struck by a die to create a nickel, plus the dings from circulation - which are probably a lot worse than average due to the flat surface.
-----Burton
50+ year / Life / Emeritus
ANA member (joined 12/1/1973)
Life member: Numismatics International, CONECA
Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club
Owned by three cats and a wife of 40+ years (joined 1983)
Author: 3rd Edition of the Sample Slabs book,
https://www.sampleslabs.info/