Néstor served as Assistant Conductor at the Opéra de Marseille during the 2018/19 season. He assisted Principal Conductor Lawrence Foster and guest conductors:

• Paolo Arrivabeni,
• Roberto Rizzi Brignoli,
• Robert Tuohy,
• José Miguel Pérez-Sierra,
• Nader Abassi and
• Mark Shanahan 

for the following opera productions:

• Boccanegra,
• Candide,
• Donna del Lago,
• Traviata,
• Faust,
• Nozze di Figaro,
• Turandot and
• Rigoletto.

In addition, he worked with the singers:  

• Nicole CAR,
• Étienne DUPUIS,
• Enea SCALA,
• Sophie KOCH,
• Leo NUCCI,
• Olesya GOLOVNEVA,
• Juan Jesús RODRIGUEZ,
• Nicolas COURJAL,
• Riccardo MASSI,
• Alexandre DUHAMEL,
• Karine DESHAYES,
• Varduhi ABRAHAMYAN,
• Edgardo ROCHA,
• Nicola ULIVIERI,
• Sabine DEVIEILHE,
• Jack SWANSON,
• Nicolas RIVENQ,
• Jean-François BORRAS,
• Christian FEDERICI,
• Mirco PALAZZI,
• Patrizia CIOFI,
• Anne-Catherine GILLET,
• Antonello PALOMBI,
• Ricarda MERBETH,
• Ludivine GOMBERT,
• Jean TEITGEN and
• Armando NOGUERA.

and conducted the following concerts:

• Festival Roque d’Anthéron 2019
• Misa Tango with the CompanyJulian Lestel
• Concerts for the programme Musiciens au Collège