I'm not so sure that Tulsa was better than NIU? Possibly? I think Tulsa's offense is better, but NIU has a pretty darn salty defense because they were really good last year and returned nearly everyone.
A salty defense that gave up 45 points to Kansas, 49 points to Wisconsin, 48 points to Central Michigan, 60 points to Toledo, and 38 points to Ball State. Maybe I'm missing something, but I don't think salty defenses give up those kinds of point totals.