Go onto LS1Tech and look up my HOW TO: thread on how to build your own Nitrous Timing Retard box. There was some quite constructive discussion that myself and a few other members had regarding how it can be setup for differing vehicles. It can be configured for multiple stages and multiple different timing retardation settings and requires about $20 in parts and about a beer's worth of time to do while BS'ing at your coffee table. This coupled with the corresponding tune modifications will allow for full timing while not spraying and automatically retarded timing on the shot. The basic gist is that it modifies the IAT signal when activated, which in turn makes the ECU pull timing in that section of the IAT spark table in the tune which keeps things safe.
With that said, since the total retardation of spark timing is only likely to be 2-5 degrees, and only in the cylinder load and RPM areas of the High Octane Spark table that pertain to "when" you are spraying the shot, even if you didn't do a timing retard box like I previously mentioned, your car won't be super sluggish or anything. It will leave a little power on the table up top, but not really sacrifice much on the bottom end unless you spray your shot directly off of the launch. Either way, NONE of this will be so much so as to affect driveability. Good luck and have fun!
EDIT: If you use EFILive instead of HPT to tune your car, then there is a section of the tune that can be dedicated to nitrous timing retardation if a certain unused pin from the ECU is grounded. I haven't personally set a tune up with it yet, and thus do not know off the top of my head what cars are and aren't supported with the "unused ECU pin" approach, but it may be worth looking into if that is the tuning platform used.