Due to a bug in Nexuiz that dates back over a year (probably even 1.0 was affected), respawn delay was always two seconds. In the source code, however, half a second was intended (it was just a confusion between two fields dead_time and death_time; whoever gave the fields these names deserves to... well, nothing). You can adjust this respawn delay in Nexuiz 2.2.3 using the cvar g_respawn_delay. Now what to do?
Note that you should also try LMS or g_forced_respawn 1 - that always spawns as early as allowed, and IMHO gets quite annoying in LMS when you can't relax for even half a second when you just got shot.