IIRC every team has to be on BTN twice each season. Do you guys have a start time/channel for the Northwestern game yet? That's prime for an 11 a.m. start on BTN.
You are correct that every team has to be on the BTN at least twice and has been mentioned in this thread, one of those telecast's must be a conference game.
Interesting nugget about the TV selection process, twice throughout the season, the BTN can pick their games ahead of ESPN/ESPN 2 (the selection order is normally ABC, ESPN/ESPN2, & BTN). With that said, i'm sure the BTN is loving the posibility of leap froging ESPN/ESPN 2 & have one of Nebraska's marquee matchups with Michigan, Michigan St. or Penn St on BTN. Some people might think of the BTN as a "secondary channel", but it's a major cash cow for the conference and is in over 80 million homes across the country.
Just like the Big 12, TV info for most October & November games (other than for previously announced Oct. night games) are announced on a 6-12 day window, but in late May, you are probably right that Nebraska's game with Northwestern has a BTN telecast written all over it.