Are you looking for the best green nail polish brand? There aren't many brands that make the green color because it is not sought as much as the other colors, for example, red, purple, etc. One brand that gets great reviews is the Opi nail polish brand. Most of the YouTube green nail polish tutorial videos that I see online are using Opi brand. I wouldn't recommend brands that charge a much cheaper price than Opi. If it looks better, then you should spend that extra few dollars for higher quality.
You can get Opi green nail polish on Amazon here:
OPI Nail Polish Green-wich Village NLB69
Here is a review from somebody who put up a video about Opi: