\Nix"ie\, n.
See {Nix}.

\Nix"ie\
1. Nothing. [Slang]

2. (U. S. Mail Service) A piece of mail matter which cannot
   be delivered, either because no post office exists at the
   place to which is it addressed, or because there is no
   place of the name mentioned in the designated State,
   Territory, or the like. [Cant]