He honed his skills at Tanglewood on a Serge Koussevitzky Fellowship with such masters as Leonard Bernstein, Seiji Ozawa, Erich Leinsdorf and Igor Markevitch, before assisting Kurt Masur with the New York Philharmonic Orchestra.
Nowak has conducted operatic productions in Italy, Monte Carlo, Switzerland, Germany, Poland, the United Kingdom, Sweden, the United States and Canada, including works by Mozart (The Marriage of Figaro, Don Giovanni, Il Seraglio, Così fan Tutte, The Magic Flute), Rossini (The Barber of Seville, Semiramide), Beethoven (Fidelio), Bizet (Carmen), Borodin (Prince Igor), Moniuszko (Halka, Haunted Manor), Verdi (Otello, Don Carlos and the Polish première of Simon Boccanegra) and Puccini (Madam Butterfly, La bohème, Turandot and Tosca – including a tour with Welsh National Opera).
His production of Debussy's Le Martyre de Saint Sébastien was broadcast live from Rome on the Eurovision television network.
Diapason in Paris praised his KOS CD with Martha Argerich and Sinfonia Varsovia as 'indispensable... un must',[1] and the second edition of this recording won the Fryderyk Award.
The American Record Guide praised Nowak's Gallo label CD of Frank Martin Violin Concerto with Piotr Milewski and the Biel Symphony as 'by far the best'.
His Haenssler-classic disc[permanent dead link] with Anja Silja won two Classical Internet Awards, and his recording of Czerny Symphonies No.