EC 1703 then EC 4796 at Madrid
Nice → Madrid → Nantes
Timetable, Madrid time
20:40EC 1703 from Nice at the gate
12:45EC 4796 to Nantes leaves the gate
16 h 05 apart on the timetable, overnight
EC 4796 leaves 16 h 05 after EC 1703 arrives on the timetable: more than half a day, so not a connection we count.