Nebraska does not provide special admission rules for government attorneys licensed in other jurisdictions.
However, Nebraska provides a Multijurisdictional Practice Rule (MJP) within its rules of professional conduct. Comment 16 to that rule provides an interpretation that exempts government attorneys from the unauthorized practice of law.
Please also see the Nebraska Bar Reciprocity page to view the requirements for Admission on Motion and the Nebraska Pro Hac Vice page to view the requirements for admission to a particular proceeding.