The town centre is only 20 minutes or so by tram from the Audencia Business School so we recommend booking accommodation in the centre. The airport is also well connected from there.
Audencia has preferential tariffs with the following hotels, which can be obtained by calling them directly and mentioning that the guest will be attending a conference at Audencia (no guarantee however that the tariff over the phone will be cheaper than the usual price comparison/booking sites)
Radisson Blue, 6 Place Aristide Briand, 44 000 NANTES ( This is one of the best options, it is an beautiful old court house converted into a hotel)
MERCURE NANTES CENTRE GRAND HOTEL, 4 Rue du Couedic 44 000 NANTES
HOTEL OCÉANIA Hôtel de France 24 Rue Crébillon , 44 000 NANTES
Other recommendations are the IBIS chain and the OKKO HOTEL (15 Rue de Strasbourg, 44000 Nantes).