Neb. Rev. Stat. § 81-8,213

No suit shall be permitted under the State Tort Claims Act unless the Risk Manager or State Claims Board has made final disposition of the claim, except that if the Risk Manager or board does not make final disposition of a claim within six months after the claim is made in writing and filed with the Risk Manager in the manner prescribed by the board, the claimant may, by notice in writing, withdraw the claim from consideration of the Risk Manager or board and begin suit under such act.