Nitric Oxide is part of our biochemistry, normally. Made on site where needed......
popping pills is like drinking oil by the gallon because your zipper is stuck. No way to live, really. Everything we can pour down our gullets has to get by a thousand wrong places to do the good you want.
However, a Jazzgal sort or a male who can't run an imaginary but effective vision capable of sufficient interest and effect, can try some beet products. Maybe some other stuff, I dunno, etc etc
On the radio, on KFI, there was a segment on nitric oxide as an effective anti-Covid agent. It's effect is to be expected, due to it's oxidizing chemistry, like chlorine and ozone. As a gas, it can be added to the respiration at an appropriate dose, for direct effect..... just like chlorine and oxone.
A few facts.
The Covid virus has a very high "binding coefficoient" meaning it sticks where it lands, on a cell surface. It has this stickiness due to having some lipid content in its anchor, much like a cell membrane, containing unsaturated oils EFAs and such. Or amino acids like lysine in high regional proportions.
Ozone reacts instantly and totally with unsaturated C double bonds, forming an epoxide that will break up where ever it is. Chlorine will do something similar, but forming a clorocarbon.
Almost any chemical with bleaching power will prove effective, but hey, use some sense, we don't want to overdo bleaching our lungs or any innards.