Nierhaus joined Deutsche Hospitality in November 2020. In 2022, the company doubled its keys in the Middle East, reaching over 1,531 keys with the opening of four new hotels. It has 29 properties across the U.A.E., Oman, Saudi Arabia, Qatar, and Egypt. Over the last 30 years, Nierhaus has worked with Sheraton, Concorde, Hilton, Carlson, Rezidor, and Steigenberger, managing the openings of over 15 hotels across the world.