The Battle of Nashville was December 15 and 16, 1864. With the collapse of the Army of Tennessee on the afternoon of the 16th, the retreat and pursuit began immediately. December 17 and 18, 1864 was the time period of the retreat from Nashville. The retreat was a running gun battle between the rear guard and remnants (and I emphasis those two separate characteristics) and the Federal pursuit. I do not recall immediately if Cheatham became a part of the rear guard. I believe at this point it was Clayton's and Stevenson's Divisions that were the rear guard.

I hope this helps.

Respectfully,

Gerald D. Hodge, Jr.
M.A. Military History - Civil War Concentration
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment