here is a case by Tadd KA2DEW

In his own words:

It uses
(4) M2.5 15mm screws
(4) M2.5 nuts
(1) M3 10mm screw
(1) M3 square nut

The nut is captive (actually it slides into the finished print) so it may have to be the specific unit. It's called a “thin” and sold by McMaster.com as https://www.mcmaster.com/97259A101/. It's an ideal nut for being captive.

The M2.5 parts are not particular. I could have used M3 parts in the NinoTNC but the shell I started with was for a Raspberry PI and M3 parts wouldn't fit. I may make a mod of this so the 10mm M3 parts would be used all around. If anybody wants that, I'll do it.

The little slot in the bottom-middle of the back is to help push the insides out of the shell. The screw in the back is to keep the insides from coming out.

The one thing I wanted in a 3d-print NinoTNC box was to have the LEDs protrude further than I'd seen. To do that I made the front panel really thin.

No supports are needed if you print the inside part LED-side down and the shell with the connector-end down. I used PETG.