Neb. Rev. Stat. § 76-269.01

On and after September 9, 1997, no action may be maintained to set aside any deed of conveyance executed by a personal representative of an estate prior to September 9, 1993, upon the grounds that the personal representative lacked authority conferred by the will of the decedent to convey real estate without court order or that a court order authorizing the sale of the real estate was invalid.