Neb. Rev. Stat. §§ 48-636
Except insofar as reconsideration of any determination is had under sections 48-630 to 48-632, any right, fact, or matter in issue, directly passed upon or necessarily involved in a determination or redetermination which has become final, or in a decision on appeal which has become final, shall be conclusive for all the purposes of the Employment Security Law as between the Commissioner of Labor, the claimant, and all employers who had notice of such determination, redetermination, or decision. Subject to appeal proceedings and judicial review as provided in sections 48-634 to 48-644, any determination, redetermination, or decision as to rights to benefits shall be conclusive for all the purposes of such law and shall not be subject to collateral attack by any employer.
Neb. Rev. Stat. §§ 48-636