Alternatively, if control of the Senate is at stake, turnout could be relatively high. There is no way to know exactly how many people will vote at this point.
If control of the Senate is at stake, Nunn would be doomed. Whatever crossover support and right-leaning independent support she's getting now would evaporate instantly.
Strictly speaking if the Senate is going to change control it will have already done so by the January 8th runoff. A Nunn victory would only move the 50R-49D chamber to an even split
An even split = Democrat control. Joe Biden would be staked permanently in Washington, DC to break ties.
Well, when the Senate is in session. It could make it awkward for him or any Democratic Senator (including Sanders) to run for the Presidency.