Different ways to do it. You can use a cheap pump just for the nitrous side if you want. Use a Holley 803 regulator dead-headed and you will be fine. That pump will only need a -8 in and a -6 to the front. No need for a return.
You DO want to have a seperate regulator for the nitrous side so you can tune the system. Buying a ton of jets isn't the way you want to tune the fuel side.
You can probably put a distribution block on the motor and feed your main pump into it. Put the two regulators on it. That's only if you know your current pump is big enough for the motor and for the nitrous system.
i have a extra holley pump laying around so i was gonna use that....also what does "dead-headed" mean? that theres no return? would it need the 8feed or the 6an be enough?