Apple - Is there a way to refresh a Finder file listing?

Yes!

A simple AppleScript can instruct the Finder to tell its front window to update every item. Such an AppleScript can be saved as an Application and then dragged to the Finder toolbar to give you a refresh button.

The AppleScript you need is quite simple:

 tell application "Finder" to tell front window to update every item

Paste the above text in Script Editor (in the Utilities folder), then use Export -> Application. THAT executable should be dragged, with CommandOption, to the Finder toolbar (that is, the top bar, not the sidebar).

You can change the icon following this answer.

To relaunch the Finder:

1. Hold the Option key and right-click the Finder icon in the Dock, then select Relaunch.
2. Press Option-Command-Escape or choose Force Quit from the Apple menu, then select the Finder and click Relaunch.
3. Log out and log back in to your user account.

I've noticed that changing the view in Finder seems to refresh the content of the Finder window. What I mean by changing the view is going from e.g. Icon view to List. I've not done any extensive testing, but it did the trick for me last night when I copied a file into the NAS box in the Terminal, while the directory I copied the file into was also open in Finder.