You don’t have enough information to determine whether it’s statistically impossible (if you’re trying to say it’s bias against Nebraska). We don’t know how often offensive holding is called on pass plays overall, and we don’t know how often holding actually occurs.
Here is a link that has some info on all offensive holding calls from 2015-2017. Nebraska isn’t even ranked at the bottom for holds per play defended. Michigan is. We’re ranked 11th out of 14. And at the top are the Big Ten darlings Indiana and Minnesota.
https://mgoblog.com/mgoboard/b1g-offensive-holding-statistics-harbaugh-era-updated-play