According to this Bismarck Tribune article, Jodi Gillette of the Standing Rock Sioux tribe and director of the Native American Training Institute will be serving in the White House as the deputy associate director of the Office of Intergovernmental Affairs. 

There are five Native American reservations within the boundaries of North Dakota.  If I understand correctly, each is a sovereign nation positioned geographically in North Dakota. 

According to the article, Gillette will help with tribal, local and state interactions with the federal government.