When Nebraska secondary coach Evan Cooper surprisingly resigned from his position in the middle of the summer, Matt Rhule was lucky to find a new and dependable DBs coach this late in the offseason. But that’s what happened, per Rhule, with John Butler. The longtime Buffalo Bills secondary coach called it quits from that post after the 2023 season, and has previously worked at Minnesota, South Carolina and Penn State, as well as at some smaller schools.He’s certainly experienced. Plus, Rhule says Butler is a guy he knows and can trust, and is excited to see the new visions the NFL veteran has …