Nadja Breytenbach was born and grew up in the capital city of Windhoek. She is a graduate in Honours of Psychology.
On 6 July 2019, Breytenbach first participated at Miss Namibia 2019 competition. She won the pageant which was held at Windhoek Country Club Resort and Casino in Windhoek. Her court included Julita-Kitwe Mbangula was chosen as the first runner-up while Johanna Swartbooi was selected the second runner-up.
She was crowned by the outgoing titleholder Selma Kamanya, Miss Namibia 2018. As Miss Namibia, Breytenbach represented her country at Miss Universe 2019 pageant, but did not make to the top 20.