I know this sounds crazy, but I don't think Schiano will ever leave Rutgers no matter the offer. He's a very religious guy and believes this is where God wants him to be.
Keep in mind he was offered the Michigan job and Miami job (some said this was his dream job) in the mid-2000s and he turned them down. I also know for a fact that he never would have left Rutgers for the NFL if he knew the Big Ten invite was coming. Paterno was his mentor and he thinks his place in this world is to turn Rutgers into what Paterno did for Penn State.
Obviously, it's Nebraska and it's one of the best jobs in College Football though, so you never know.