LL 5481 then FR 4545 at Barcelona
Nantes → Barcelona → Porto
Timetable, Barcelona time
14:25LL 5481 from Nantes at the gate
06:45FR 4545 to Porto leaves the gate
16 h 20 apart on the timetable, overnight
FR 4545 leaves 16 h 20 after LL 5481 arrives on the timetable: more than half a day, so not a connection we count.