NIU is one of the best teams in the MAC. NIU is not a team that can be taken lightly, and I can assure everyone that Tressel and staff won't take NIU lightly - Even with Texas looming. That's based on having watched Tressel manage this team since his arrival.
NIU has enough talent to stay on the field with OSU, they don't have the depth. However, if things bounce thier way, if OSU is flat, NIU could indeed put a scare in to OSU, or even beat them. Now, I doubt that NIU will indeed beat OSU, as I feel Ohio State's superior talent and depth won't fall apart entirely - certainly not in the first game of the year - when I expect everyone will be itching to hit someone not wearing the same color as you.