although I've no idea of Linux internas, I will happily try the mentioned "modprobe nvaudio" into the /etc/init.d/boot.local file.
Because my Epox 8RDA+ board (also with Nforce2 chipset) won't play any sound so far, with Suse Linux 8.2 that is.
Of course I installed Nvidia's Linux driver for the chipset. Then the onboard LAN does work (which didn't without the driver). But sound doesn't.
Well, I'll report if it does the sound trick for me, too.