To clone a Mosaic virtual display

You can clone a single-GPU Mosaic display onto a physical target display. The target clone display can then be used, for example, as a confidence monitor.

Make sure you have set up your Mosaic configuration as well as securely connected the additional displays you want to use and enabled them.
From the NVIDIA Control Panel navigation tree pane, under Display, click Set up multiple displays to open the page.
If any displays are in Clone mode, right-click the display icon box of the Clone group, click Extend, then click Apply.
Right-click the display icon for the Mosaic virtual display that you want to use as the source display to clone.
From the pop-up menu click Smart clone with, then click the display you want to use as the target clone display.
Click Apply.

The icon numbers corresponding to your displays appear in the same box icon.