So far we know a few things.
1) Chosis is very likely to be behind lamboticket.com
so this $300,000 winning amount has likely been conjured up by him to sell ad space on his own site and reap the profits. I think he plans to make up a sock puppet "winner" who posts here as anon claiming he got the payout so that future contests are even more popular = more money for chosis.
2) Chosis is a known bitcoin/turtlecoin fanatic and actively discusses these kind of schemes on /biz/
3) Chosis has been known to lie. He claimed to have cancer a while ago and has repeatedly been caught manufacturing drama by turning his trip on and off to make it seem as if he has a large following in any thread he creates.
4) Chosis has mentioned before that he is in some financial distress. He has multiple altcoin donation links on his site and is trying to sell prints of his work for way more than they're worth. He's also mentioned that he invested a lot into bitcoin last year and admitted last year he spent about 40k on camera gear alone in another thread.
5) Chosis deleting negative comments and banning people for questioning this contest shows it has extreme personal importance to him personally despite him claiming he's just promoting another unrelated person's giveaway. This is his scheme and he's determined it look legit so it works out for him financially hence banning 4chan users from his supposed 4chan promoting Instagram. He has never cracked down on 4chan being 4chan before now.
Anyway, he's a faggot and this scheme is doomed to fail.