AA 2258 then FX 9791 at O'Hare
Las Vegas → Chicago → Anchorage
Timetable, Chicago time
12:52AA 2258 from Las Vegas at the gate
04:00FX 9791 to Anchorage leaves the gate
15 h 08 apart on the timetable, overnight
FX 9791 leaves 15 h 08 after AA 2258 arrives on the timetable: more than half a day, so not a connection we count.