I've smoked every day of my life for the last 8 years. I'm not worried about it making me panic.
All I'm asking is abt the chemical interaction with SN.
Weed shouldn't interact with SN chemically, at least I can't think of any obvious pathways that would. Cannabis acts on the endocannabinoid system whereas SN reduces hemoglobin to methemoglobin, and neither of those processes are particularly closely related. The only overlap that seems likely to me would be in certain side effects, like higher heart rate. Even then, since you use it so regularly I would guess those physical effects are probably not super strong to begin with which makes it lower risk. Ultimately it's up to you to gauge the risk, based on how weed affects you, and decide if you're comfortable with it.
Also, regarding it not being a "strong enough" antiemetic - I think that's a tenuous claim. An AE is not strictly necessary with SN and most people who drink 20g succeed even if they do vomit, so it's really more of a comfort measure that, at best, could slightly increase the chance of success.