sorry to be a pain but a few years ago endless bees triied converting NaNO3 -> NaNO2 (Ab2 included) we all wasted alot of time (and NaNO3) some destroyed their hotplates and glass with Xtreme temps, but no one was successful at anything other than a series of failed reactions. Some poor optimistic bastards even triied to use thier pretend NaNO2 in subsequent reactions that also failed miserably, carrying a small fortune in precursers down the toilet with them.
Not saying it is impossible, but definately rough love.
NaNO2 is cheap and unwatched, you can say its for meat preservative if anyone asks.