If you want to see a show while you're in town, try and grab some tickets at Musiktheater in Innenstadt. If you enjoy the show and want to see another, Linz State Theater and Brucknerhaus Congress Centre are both not far.
Nordico Museum is just one of the attractions in Innenstadt, Linz so you might want to stop by during your trip. If you want to experience more of the culture Linz has to offer, head to Linz Main Square, St. Mary's Cathedral, and Linz State Theater.