Viewers: The number of viewers aged 2+ viewing the game in the average minute. Navy-Notre Dame averaged 3.56 million viewers per minute. (That does not mean 3.56 million viewers total watched the game. Nielsen uses a separate total viewing figure to estimate how many viewers watched at least six minutes of any given telecast. Typically, that figure is significantly higher than the average viewership listed here.)
So this doesn't account for people who tuned in for the first half then changed the channel when FSU got their shit sorted and LSU did not. I bet this Nielsen fellow would have CU @ TCU over LSU v FSU if there was a measurement of complete program viewership.