well, SWISS 'indicates' only 60 minutes minimum connection time for JFK - but guessing that the UA segments will be on another ticket (and not be 'protected') I (non US passport-holder) would, at least (to be on the 'safer' side) 'calculate' 120 minutes (immigration time depends if US-passport holder or not), and I would bring my checked-in luggage myself for re-checking with UA.