You may use these as level codes however not all seem to be
accepted while others don't warp you to any Level.
If you want to reconfirm what I found just check the NUKEPC.EXE
at offset 43550 (hex) and process the bytes you find there.
Example:
First level pw is: JUNGLEWAR
It is to be found at the mentioned offset like that:
0A 1D 06 0F 0D 1F 11 22 17
Decode that as follows (very simple algorhythm):
(byte + 3C) XOR 0C = value -> e.g. (0A + 3C) XOR 0C = 4A ('J')