Nebraska Statepaper.com reports that the state's Supreme Court has upheld the term limit measure passed by voters back in 2000. According to the Court:

The first power reserved by the people is the initiative whereby laws may be enacted and constitutional amendments adopted by the people independently of the Legislature ….

A constitution represents the supreme written will of the people regarding the framework for their government. The people of Nebraska may amend their Constitution in any way they see fit, provided the amendments do not violate the federal Constitution or conflict with federal statutes or treaties. This court makes no attempt to judge the wisdom or the desirability of enacting initiative amendments. The party challenging the constitutionality of an amendment bears the burden of establishing its unconstitutionality. [emphasis added]

The Court's decision is available in PDF here.