From what I have found, yes, it must be paid.
http://dol.nebraska.gov/webdocs/Resources/Statute/Wage%20Payment%20and%20Collection%20Act.pdf
6) Wages means compensation for labor or services rendered by an employee, including fringe benefits, when previously agreed to and conditions stipulated have been met by the employee, whether the amount is determined on a time, task, fee, commission, or other basis. Paid leave, other than earned but unused vacation leave, provided as a fringe benefit by the employer shall not be included in the wages due and payable at the time of separation, unless the employer and the employee or the employer and the collective-bargaining representative have specifically agreed otherwise. Unless the employer and employee have specifically agreed otherwise through a contract effective at the commencement of employment or at least ninety days prior to separation, whichever is later, wages includes commissions on all orders delivered and all orders on file with the employer at the time of separation of employment less any orders returned or canceled at the time suit is filed.
