Another chance to hear David Pountney talk to Michael Oliver about the challenges involved in staging Verdi's early masterpiece "Nabucco", first produced at La Scala, Milan, in 1842, and revived at English National Opera earlier this year. Set among the decadent splendours of ancient Babylon, its famous Chorus of the Hebrew Slaves became a powerful symbol of Italian nationalist feeling in the mid-19th century. (R)