I took the time to track down each school's official Pantone-registered colors. Remember that these colors may look slightly "off" because these are the actual Pantone colors as reported by the various schools' identity and branding guidelines.
Note that different fabrics, papers and other media will "represent" the color slightly differently. A shiny football jersey will look different than a matte-finished baseball uniform, even if it's the exact same color.
Also, your monitor settings can play tricks with the eye as well.
As you can see, Georgia, Arkansas State and Ohio State are almost identical to Nebraska - at least to the naked eye. Even NC State, Wisconsin, Maryland and Arkansas are all also really close and probably wouldn't look too much different on the field.
It's not until you get to the more "maroon" tones of USC or Stanford that you really notice a difference.