Didn't want to start a new topic on this.
I figured it out - with a ChromeOS keyboard, you can use the key combination Ctrl+Shift+Refresh (on a ChromeOS Keyboard, this is along the top row - where function keys are on a PC keyboard - and looks like a open circle with one arrow at the end.)
I've run into an issue with one of the four Chromeboxes I need to re-orient the screen. The key combo doesn't work. I'm also locked out of the settings in ChromeOS on the device. I tried to remote desktop to it, but get a message that the device cannot be located.
I provisioned this Chromebox the same way I provisioned the other three, and those let me rotate the screen using the key combo. I'm stumped.