You would've seen Bob walk out on stage, You would have seen him perform three songs, including a charming version of "I Threw It All Away", as well as reprising his duet with Cash on "Girl of the North Country" that arguably improves on the album version by virtue of being a tighter, more focused take (Bron Every Bob Dylan Song)
And you would have been even more surprised to hear a song that had never appeared on an album before, another low-key country song (a cover? an original?) with some nice backing from Cash's house band. That song would be "Living the Blues", a Bob Dylan original, and one of the highlights of Self Portrait (indeed, it probably would've been one of the highlights of Nashville Skyline). Why he played it on TV instead of, say, "Lay, Lady, Lay" is anybody's guess, but it's a pretty cool thing that he did, one of those strange side roads in Dylan's career.(Bron Every Bob Dylan song)
The Freewheelin' Bob Dylan. Dylan re-recorded the song as a duet with Johnny Cash in February 1969. That recording became the first track on Nashville Skyline, Dylan's ninth studio album.