UA 6047 then AA 6233 at O'Hare
Pittsburgh → Chicago → Nashville
Timetable, Chicago time
20:31UA 6047 from Pittsburgh at the gate
18:18AA 6233 to Nashville leaves the gate
21 h 47 apart on the timetable, overnight
AA 6233 leaves 21 h 47 after UA 6047 arrives on the timetable: more than half a day, so not a connection we count.