Nowak was ordained a priest on 10 May 1956 for the Diocese Paderborn.
On 12 February 1990 he was appointed Apostolic Administrator of Magdeburg and the Titular Bishop of Cissa. He was created bishop on 24 March 1990. The main consecrator was Johannes Braun, his predecessor as Apostolic Administrator of Magdeburg, and co-consecrators were Johannes Joachim Degenhardt and Theodor Hubrich. On 27 June 1994 he was appointed bishop of Magdeburg and installed on 9 October 1994.
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