really weird. :S
i'm using a mac and didn't notice that problem... you should actually see several files, applications and folders in the Nexuiz base folder after uncompressing.
1. Where did you download Nexuiz ? if you did download somewhere else, i would suggest you to download Nexuiz 2.0 from
an official mirror
2. What is the size of the archive you downloaded, perhaps the download was stopped or something like that...
3. Do you use a special software to uncompress, or did you do it with the default system uncompression tool ?