Does the State of Nebraska have an Open Meetings Law
Yes!
was the public or the school student body ever notified of their meetings behind closed doors,
It was not unlawful for the affected student athlete, student body, or the public to be noticed of the meeting. The following Attorney General's Opinion should answer your question.
"Committees of faculty, administration and students created by the Board of Regents of the University of Nebraska to advise the Chancellor of the University in his administrative/management function with respect to budget cuts were part of the management structure of the University and not public bodies subject to the open meetings statutes. Op. Att'y Gen. No. 92020 (February 12, 1992)."