I bought Nair a while ago to use on my legs, and am not too impressed with it.
It is messy and not easy to apply evenly. I’ve tried it a few times over a period of about a year, and have never seen any significant results. You have to let the hair grow out to an annoying length in order for it to be any good at all, and even then, I’ve never seen it do much for my legs. They feel so nice the next day after I shave them.
I also tried using Nair on my arms, because on my upper arms I have some coarse, dark hair that I wanted to get rid of. Turned out, the first time I tried, the stuff only removed the lighter, fine hairs. I used it again a couple days later, and it did remove most of the darker hair that time. So, Nair mostly worked on my arms, and mostly does not work on my legs.