Aquila There is no "best value" nits for indoor use in the night.
Your best nits should match (or be slightly dimmer than) your surrounding desk environment.
Here's how you could do it:
Since you have the built in brightness setting in the Nvidia Control Panel software, you can take advantage of that to prevent PWM on your monitor.
Ensure that your monitor (in the physical monitor hardware brightness is at 100%). Put a paper 90 degree at either side of the edge of your monitor screen. Using the Nvidia Control Panel, reduce the brightness until light from the monitor no longer hit on your paper. Then you reduce the contrast until your comfortable level.
Should you feel that the screen contrast is still too bright for you, you can further reduce the constrast level on your physical monitor.
That's what I did for mine and it worked like a charm.
(source: I did a course on reducing fatigue in the workplace before and also a number of forum members that have shared their experience)