I was told that it would be a good idea to run a independant fuel system for a NOS system? Is this correct and if so what are the benefits?

The short answer is yes, its a good idea if spraying a larger shot.
It's overkill for a shot in the 100hp range.

The benefit is that you completely eliminate the chance of creating a lean condition when spraying (you are no longer "pulling" fuel from your cars fuel system for the N2O system). You can also run an expensive, high octane fuel and not break the bank doing it (compared to having to fill your cars tank with it).