I just discovered the solution for this with some helpful hints from opensuse forum moderator wolfi323. Since I couldn't find it here, I post it now, so it might help others:
Opensuse version is 13.1
Nvidia drivers tested are G02 (old cards) and G03
xbmc versions tested are Gotham as packaged on pacman and compiled from source. I also tested from todays git.
All combinations show the same result: when the xbmc/kodi fullscreen is displayed, there is no text in the menues.
The problem is a conflicting package Mesa-libGL1.
I had to force xbmc/kodi to use the Nvidia libGL by setting the library path.
as root (needs re-login to take effect):
echo "export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/X11R6/lib64:/usr/X11R6/lib" >/etc/profile.d/force-nvidia-GL.sh