Nexuiz crashes on my monster-upgraded rig.
What i got

WindowsXP sp2
1gig ram
GeForce7300GT (on AGP 4X)
AMD Duron 800 Mhz <-Funny story...

The card seems to throw a fatal error on anything opengl.
Seriously, WTF?

Well if it crashes on anything opengl it can hardly be a Nexuiz problem at least one good thing
But maybe someone has an idea if you post the error message from the Nexuiz log. Start it with parameter -condebug that will make it create a file qconsole.log that should contain an error message.
Maybe the driver install was corrupt and a reinstall will help.

What drivers? Have you tried other drivers?

Don't worry about the hardware, there is no reason why a 7300GT should not run Nexuiz, it will in fact run it very well, there must just be a configuration/driver issue.