BA 349 then BA 209 at Heathrow
Nice → London → Miami
Timetable, London time
21:05BA 349 from Nice at the gate
14:30BA 209 to Miami leaves the gate
17 h 25 apart on the timetable, overnight
BA 209 leaves 17 h 25 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.