Quick answer: use the Affidavit for Transfer of Decedent's Vehicle/Motorboat, attach the title (if available) and a death certificate, and present it to the DMV.
A dedicated affidavit, straight from the DMV
More than just cars and trucks
This same affidavit covers motorboats, ATVs, utility-type vehicles, and minibikes, in addition to ordinary cars and trucks — a broader list than many states' vehicle-specific affidavits offer.
An exception for very old, already-closed estates
If the estate closed 10 years ago or more, the DMV waives the no-personal-representative-pending rule when proof the estate closed is shown along with a certified death certificate — useful if a vehicle title issue only surfaces long after everything else was settled.
Joint titling can skip the affidavit entirely
If the title lists a joint owner with "or" rather than "and," the surviving owner can typically transfer it as a simple sale from there, without needing this affidavit at all.
A local probate attorney can review your estate — many offer a free consultation.
The Nebraska DMV processes this affidavit the same way statewide, regardless of which county's County Court would otherwise handle a formal estate.