Saw Nabucco last night at the Met, thanks to a generous dear friend visiting from out of town. Now, it's not one of Verdi's best. But the chorus in Act III is a showstopper. It made me wonder though: isn't 2+ hours a long time to sit through just to hear one of the all-time great choral numbers? I'm not sure. Verdi was famous for being able to accurately take the measure of his own music's popularity. And the chorus sung by the Israelites in Act III is no different.
Here's some video from the current Met production. Notice that no one moves on stage during the entire number. And yet, with this particular number, it doesn't seem to matter. Not so with the rest of the opera, I'm afraid.
In fact, one funny Verdi story comes to mind. In Rigoletto, he apparently held back the sheet music to La Donna e Mobilie until dress rehearsal cause he was so sure it would be an instant hit. And he was right.