I doubt she'll get more then a fraction of that but on the face of it winning is a real possibility. The drama is sold as a true story (whatever has been said elsewhere) and they used real messages that are publicly available so finding the real woman was fairly trivial. She's had personal consequences off the back of lying about her.
I doubt gadd has that much cash to sue for hence netflix. Whether netflix needed to do due diligence to ensure individuals are protected or they can turn that back on gadd will depend on their contract, the law etc.