BA 349 then BA 179 at Heathrow
Nice → London → New York JFK
Timetable, London time
21:05BA 349 from Nice at the gate
18:05BA 179 to New York JFK leaves the gate
21 h apart on the timetable, overnight
BA 179 leaves 21 h after BA 349 arrives on the timetable: more than half a day, so not a connection we count.