This information is available within the DRuG_NOS tab on the server's f9 menu... I've just tested changing to normal from nfs using /noscontrol normal - it confirms the change in the middle bottom of the screen.
Hope this helps...
/nosgauge [on|off] - Sets the NOS gauge visibility (default 'on')
/nos [normal|nfs]
/noscontrol [hybrid|nfs|normal] - Sets the NOS firing control style (default 'hybrid'):
- normal : The default sucky behavior; Once NOS is fired there's no way to stop it.
- nfs : NFS-style NOS; hold fire to start NOS, release to stop.
- hybrid : hybrid-style NOS; press fire once to start NOS, press fire again to stop.
/nossustain [on|off] - Sets whether to keep NOS turned on after the following events (default 'on'):
* Picking up a vehicle change pickup while having NOS turned on
* Picking up a nitro pickup while having NOS turned on
* Changing vehicle on a checkpoint while having NOS turned on
/move_nosgauge - Enables nos gauge repositioning.