The second edition of NADA will officially open its doors today at 2 p.m., but a crowd of VIPs and press arrived at the riverside fair as early as 9:45 for a special preview. Inside, compliments on the new space (last year NADA was staged in the old Dia Art Foundation building on West 22nd Street) abounded. “It’s pretty great having an art fair in something called ‘Basketball City,’” said dealer Bill Powers upon arriving with Karma owner Brendan Dugan. The fair, which runs through May 12, features 70 exhibitors this year, up from the first iteration’s 60. Many of the exhibitors hail from the nearby Lower East Side gallery district, but others come from the Midwest, West Coast and Europe.