The calculated distance (air line) between Saint-Philbert-de-Grand-Lieu and Nantes is approximately 13 miles respectively 21 kilometers.
By car or train, the actual journey to Nantes is certainly longer, as only the direct route (as the crow flies) between Saint-Philbert-de-Grand-Lieu and Nantes has been calculated here.
Air line (approximately)
21 kilometers
11 nautical miles