Like others have said, statistically, the Browns. Just based on the number of teams that make the playoffs. And that a team that loses 7 or so games can make the playoffs some years.
In college football it is more cut-throat and somewhat arbitrary. Only four teams get in. Probably only ten or so teams have a realistic shot going into things in the first place. And unless you win them all, you are at the whims of the committee.
OSU has a good shot, but just number wise it is easier in the NFL. At least in a sense. It is a 16 game season and so on. But you can also lose more than a game in the NFL and make the playoffs. College football, you are dead with 2 losses.