Nazi Invasion is a map set for shareware Wolfenstein, made by Jonathan Wiseman. It was released on March 28, 1999.
The map set features 9 new levels, with level 9 being based on Hans Grosse's original level. Though the secret level is accessible (though a vertical/horizontal door bug complicates its access) it is unchanged.
According to the Read Me, Wiseman mentioned he was probably the youngest person to ever make maps, though his age was not disclosed.
It is playable in SDL, being a shareware map set.