I just had my share of fun with this. Parked at work and a couple hours later I was greeted with "Low Battery" on the monitor behind the steering wheel then all the other warnings lit up when it started, then no HVAC, then no monitors.
Steps to recovery:
1) I found a local AC Delco seller nearby
2) called for the battery (LN1AGM) and found nearby place with a few in stock
3) borrowed coworkers car
4) picked up a battery with a JAN19 date ($212.11 with tax, they waived core charge)
5) stopped for lunch
6) stopped at Lowe's for ratchet set (I don't live nearby for my own tools at home)
7) swapped battery and it started
If anyone else has to do similar steps, anyone that can do "righty-tighty, lefty-loosey" can do this. It's 3 bolts, the 2 on the battery terminals are 10mm and the one holding the battery in place is 13mm. The one holding the battery will require an extension common on any ratchet set (4+ inches long).
Disconnect negative (black) first and pull aside, disconnect positive (red) and set aside, remove 13mm with plastic holder that just lifts off and pull the battery out. Reconnect negative first and then positive. I heard something in the engine bay kick on once connected so I figured that was a success.
Saved me the hassle and expense of towing and expense of someone else doing it.
Total time (with research, lunch, driving, and Lowe's): 4 hours
Thanks to everyone here for helping me make educated guesses.
2014 2LT with DCFC, 31,000 miles