Where did you see that you have 0.2 BTG in your Hashnest wallet?
Was it because the BTG option was enabled previously? If it was and you didn't do anything, your free BTG may have been lost. Hashnest said that they would support the BTG fork temporarily and would let their users withdrawal the coins after the fork, but they wouldn't support it forever. Maybe the time to claim them is over and Hashnest just decided to keep your coins?
Anyways, it's just ~$10.
Oh, I definitely skipped the information that BTG support is temporary, this is must be the reason why I can't do anything with that little amount on my balance. Yes, it's not so big, but as perfectionist I like to hold everything under control and this 0,2 with which I can do nothing annoy me a lot