AA 540 then UA 3916 at O'Hare
Nashville → Chicago → New Orleans
Timetable, Chicago time
11:05AA 540 from Nashville at the gate
07:00UA 3916 to New Orleans leaves the gate
19 h 55 apart on the timetable, overnight
UA 3916 leaves 19 h 55 after AA 540 arrives on the timetable: more than half a day, so not a connection we count.