Give it proper fuel and actually get the damn thing tuned, and you're safe up to around 200whp...which is a 75-100 shot.
Here's the thing though, forced induction is pretty much forced induction. Nitrous, like a turbo or supercharger, is only as safe as
you make it. With nitrous you're going to have limits on how you can use it and you're going to have to pay to have the bottle refilled. A turbo is power that's always on tap and is actually lower cost in the long run. Read through the article on building a homemade turbo, up in the Reference Section.