If you tuned into “NBC Nightly News” last Sunday hoping to see prime time TV coverage of Warren County, you realize the segment did not air.Producers of “NBC Nightly News” decided to postpone the air date to this weekend. The segment highlighting Cumberland Caverns and “Bluegrass Underground” is now scheduled to air Saturday at 5:30 p.m.“When the executive producer saw the footage, it was so visually stunning he wanted to hold it until Saturday night when they have a bigger audience,” said Cumberland Caverns vice president of marketing Teddy Jones. “The producer who traveled here, Kim Cornett, said it is a really good thing because with football games airing on Sunday it pulls their audience.