Donnie, love seeing your creations. One thing to keep in mind is the use of teflon tape on a nitrous sytem is frowned upon. It tends to get caught in places it shouldn't. Though I'm sure you don't wind it over the last thread or two.
Wouldn't the nozzle placement be more effective higher in the manifold so there is more residence time to cool the charge? Are you running N20 the whole pass or just to spool the turbo? Maybe even into the turbo inlet? It'll help cool the compressor, too. We use to spray directly into our blower to do just that. We would go through 150 pounds in 4-5 minutes feeding a 2,240 cid engine. (God, I hated filling those bottles all the time.) Technology has changed over the last 20 years, though. We were definately "old school" in todays world of nitrous injection. I still have some parts that were destroyed by nitrous. Maybe I'll post some pictures.
Your nozzle design looks good to me, though. I also like the retaining and o-ring seal system. Good workmanship.