If you start a timer on one device, and are near another device in another room and ask it to "Hey Google, Resume stopwatch", whatever device you're closest to either says:
Which means you then have one stopwatch running, and one paused, that you can't access because now when you ask it to pause and resume the stopwatch, it will pause and resume the one it just started.
There's no easy way to access them, not even on a Nest Hub 2nd Gen.
Assistant doesn't ask you to clarify which one you mean, or give them a name.
So it's harder to use than a stopwatch on a smartphone, or a normal electronic stopwatch.
A Nest Hub will show a stopwatch on the home screen if you started it on that device. But it doesn't have a section showing all stopwatches started in the home, or at least, ones you started with your voice. It also doesn't show stopwatches started on a smartphone that's connected to the home, including when that device is located within the Google Home.
Thanks for reaching out. Stopwatch feature is device specific. Our team is working hard to deliver the best experience for our users — we'll take this as feedback. Keep your eye on the Google Nest Community page for any updates.
Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
Check out this link on how to file feedback.