The Nemesis_Tank.zip file you have requested: Skins / Special Infected / Nemesis Tank - 1.88mb is not available. Perhaps try browsing all files for the game Left 4 Dead and upload any files you want to share or are missing. This is the only information we could locate:
Basic retexture to make the tank look like Nemesis. (Note, this skin is incomplete, and will remain incomplete till the SDK comes out.