NIAC may refer to: NASA Institute for Advanced Concepts, an external NASA program that closed in 2007 NASA Innovative Advanced Concepts, an internal NASA program that began in 2010 National Immunisation Advisory Committee, an immunization advisory committee in Ireland National Indoor Athletics Centre, an indoor track and field athletics sports venue in Cardiff, Wales National Infrastructure Advisory Council, a council of the United States Department of Homeland Security National Infrastructure Assurance Council, replaced by the National Infrastructure Advisory Council as of the signing of U.S. Executive Order 13231 National Iranian American Council, an association of Iranian-Americans Nebraska Intercollegiate Athletic Conference or Nebraska-Iowa Athletic Conference, former names of the Great Plains Athletic Conference, American college athletic conference Non-International Armed Conflict, a type of conflict defined in International Humanitarian Law Nonprofits Insurance Alliance of California, the first and largest organization in the Nonprofits Insurance Alliance Group Northern Ireland Assembly Commission, the corporate body of the Northern Ireland Assembly Northern Indiana Athletic Conference, an IHSAA Athletic Conference based in South Bend, Indiana. Northern Intercollegiate Athletic Conference, a college athletic conference in North Dakota, Minnesota and Manitoba Nuclear Industry Assessment Committee, an organization that shares auditing services among its members