Sometimes when running Chrome, a webpage or something else will cause the computer to stay awake and not allow it to sleep. I ran
powercfg -requests from the command line and discovered that Chrome was keeping the computer from sleeping. The message received from powercfg was
Uploading data. So, some webpage or part of Chrome internals was uploading data. Aside from this being a little bit creepy since nothing was being uploaded manually at the time, there is a quick fix to allow your computer to sleep when Chrome is "Uploading data".
On the Google Product Forums I found this issue answered by hunterdg.
The fix is to run this command from an administrator command line:
powercfg -requestsoverride PROCESS chrome.exe awaymode display system
If for some reason you ever want to back that change out, run:
powercfg -requestsoverride PROCESS chrome.exe