For nail fungus start by cutting the nail back as far as you can. Then file the top of the nail down a little to expose the inner nail. Remember to sterilize the nail file afterward. Next rub some thyme essential oil in to the nail. You can use Listerine (active ingredient thyme oil) or Vick's Vapor Rub as substitutes. Apply daily. As the nail grows out continue cutting it back as far as you can and filing down the infected area to apply the thyme oil. It will take time to grow all the way out, probably around 8 months to a year, so be patient.
Also make sure that you are not damaging the nail with tight shoes, or shoes that do not breathe. Keep your feet open to air and sun as much as possible to help control the fungal growth.