They're using what we used to call "whippets" for this. It is USP grade nitrous oxide. It's a bit of money for plastic bits. I cant see how the NOS is controlled, or metered.
Here's the thing though, if you add NOS to your engine under load, you're immediately going way lean. A hip pocket statement here, but in order to get any appreciable power, you need to squirt an appreciable amount of NOS while simultaneously increasing fuel flow. Or, you have your fuel set up so fat off the line, that you're blowing black smoke until you hit the bottle.
This is basic engine 101. If you want this to work, you have to establish AFR at pre and post bottle settings. NOS with no increase in fuel means hole in piston.
I suspect this system is designed for constant flow that would allow a fatter fuel setting.
The Havasu Dave amateur engine guy rating is "snake oil."