I would say the majority are Donkey's or Chefs fans. Lots of bandwagoners in my experience though. Packers fans came out of nowhere a few years back, same with Steelers. My dad has been a Seahawks fan since 1976; he's definitely an outlier. I know a few handfuls of Cowboys fans too
When I lived in Nebraska, 60's to early 80's, my 2 favorites were #1 Green Bay and #2 Denver. Now I live in Colorado and it's the same except Broncos have moved to #1. I have always liked both.
In my group of friends we have two Ram fans, two Packer fans, a Jaguar fan, a Viking fan, a Chief fan. So based on these observations, the Rams and Packers have the biggest backing in Nebraska
I run into ALOT of Raider fans in my neck of the woods which includes my uncle, the Ultimate Raider fan. I like the Bears, aunts from the east coast so Patriots, my Dad likes the Falcons.