BA 349 then AA 87 at Heathrow
Nice → London → Chicago
Timetable, London time
14:05BA 349 from Nice at the gate
12:35AA 87 to Chicago leaves the gate
22 h 30 apart on the timetable, overnight
AA 87 leaves 22 h 30 after BA 349 arrives on the timetable: more than half a day, so not a connection we count.