AA 9866 then AA 4991 at O'Hare
Marquette → Chicago → Nashville
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
08:50AA 4991 to Nashville leaves the gate
22 h 20 apart on the timetable, overnight
AA 4991 leaves 22 h 20 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.