Neb. Rev. Stat. § 77-2112

The county court of the county wherein the estate of the decedent is being probated shall have jurisdiction in the probate proceedings to hear and determine the apportionment and proration of such tax as set out in section 77-2108 . The district court of the county of which the decedent was a resident at the time of his death, or if a nonresident of the state, of the county in which all or any part of his property was situated, shall have jurisdiction of an action in equity for an accounting and contribution after the apportionment and proration have been determined by the county court.