It HAS won GOTY, fun fact, doesnt have to be IGN, as long as some site for gaming calls it GOTY, that's all that matters. If a terrible series like God of War can win GOTY, New Vegas could definitely win GOTY
^^This. Bethesda/Obsidian just need one site calling FNV GoTY and done, they can label the edition that way. FO3 were awarded GoTY by Crispy Gamer Game Trust, Gamasutra, GamesRadar (UK), GameSpy, GDC Game Developers Choice Awards and IGN (http://en.wikipedia.org/wiki/Game_of_the_Year).
I seen something where Mass Effect 2 won last year
Now, that's a game that trully deserves the title GoTY! Not only a truckload of sites gave the award, but two very respectable critics association also gave the game the award: Academy of Interactive Arts & Sciences and British Academy of Film and Television Arts (BAFTA).
The other title that won a lot of awards in 2010 was Red Dead Redemption.