Just take it easy and like tweak that nollie, and make sure your middle finger is nice and straight across the deck like you would do with your foot for nollie/ollie with a skateboard. Its kinda the same as with a skateboard. If your foot is "off" and not straight you will loose a bit of controll and sometimes the deck will flip if you cant adjust and controll it. This can actually feel harder with a fingerboard than with a skateboard. Just keep doing nollies and eventually you will have nice, chill and steezy nollies to the point where it almost seems like slow motion and like you have all the time in the world to controll, tweak, turn, shuv, flip, late shuv, late flip or whatever. It took me what felt like ages, but just keep at it and keep it fun! To me at least this is half the fun, and when you got it down its no struggle any more, so enjoy the struggle if you know what I mean..aha..
