NE doesn't have a lower chamber, just a Senate. In most legislative documents NE is left grey for the lower chamber. Also all Senators in NE run without party affiliation in a top-two primary. I assume that you are imputing the party of NE Senators from other sources.
Nebraska has a unicameral legislature. By tradition the members are referred to as "senators". It is the largest chamber for purposes of determining who may vote for Congress (and because of the non-partisan primary actually has an effect).
