Nebraska went 60 years with two area codes, but years after an assignment frenzy in other states, three new digits are coming to the eastern part of the state: 531. That includes the entire part of the state bordering Iowa.
Unlike the splits in Iowa, 531 is an overlay of 402, meaning that no current phone numbers will change, and the entire area has to do 10-digit dialing for everything. I think splits are the better way to go, but I can imagine the overlay was preferable to a Lincoln-Omaha fight over who got to keep the old digits.