There's a wonderful resource, Wikipedia, which has good article. Here's the URI: http://en.wikipedia.org/wiki/Nitric_oxide.
As well, you might try googling on it. There are a wide variety of articles regarding the the efficacy of NO2.
Different folks, and even brands, of "supplements", have varying degrees of effectiveness, even in different individuals.
Generally, speaking, if it works well, it gets banned. LOL.
Most of the supplements are for lining the pockets of the folks making them. E.g., need 40 grams of complete amino acids? Eat a can of tuna. No point in having most the expensive pee on the planet.
From a practical perspective, however, some brands of creatine are really good, and to get vast amount of protein, a lot of proteins powders are really very good at allowing you to get that protein in.
Growth as as you call it, (I'm assuming you mean hypertrophy) is resultant of many factors. Main thing you need above and beyond all else is:
1. Stimulus / good training method.
2. Calories / anabolic state
5. Genes help, too.
You can buy a boatload of "supplements" but, if you're not anabolic for whatever reason, don't train properly, don't rest properly, and, and this is the biggie, don't eat enough..you won't get bigger..period.