The song "Tennessee Whiskey" by Chris Stapleton contains just two main chords, A Major and B Minor, the 1st and 2nd chords in the key of A Major. Minor chords are often noted on Nashville Number charts as "-". So these two chords would be described as "1" and "2-" in the key of A Major.
Throughout the song, the acoustic part does play a D/A (D over A, or D Major with A in the bass position) chord which adds a little movement to this progression. D/A would, in the Nashville Number system, be called 4/1 (the 4th chord in the key over the 1st note in the key).
Below are the chord shapes likely used in the acoustic guitar part.
A Major
The electric guitar part uses something like these two chord shapes.