I think what has saved me from any nitrous related failures is my torque converter. Having a converter that flashes to 6000+ (depending on engine) keeps the engine from ever being loaded hard at too low an RPM. Think about where the majority of nitrous explosions occur...At the hit, when RPM is down!
I've never had the slightest little hiccup using nitrous, and mine is setup on a throttle switch--I leave at an idle, but the engine flashes beyond where the typical engine would go BOOM! I also run more timing than an average guy would run; with a forged bottom end I don't pull any timing with a 200 shot, and the engine responds better so it leaves better. I hear some cars at the track with such lazy throttle response from a lack of timing, it's no wonder they backfire when the nitrous is engaged!
On the junk 350 I pull the timing back to 30° total, and add a splash of race gas for a little insurance on the cast crap iside. BTW, my distributor is locked out too, so whatever timing I run is all there all the time.
Keep the fuel pressure slightly higher than what's called for, read the instructions, follow the instructions about what jet combo to use, and you should be ok.