Nails or screws to fix tongue and groove boards on a gate?

The frame brace and ledgers are screwed. You can use compressor and nail gun for the tongue and grove boards

Course threaded wood cutting screws are good as when banging nails in everything shakes around but with screws you can set out on your bench and simply screw the boards to the framework. Some people use round headed ring shanks and let them go through the frame and bend them over....but if you do this the finish doesn't look great and you also need to remember to bend them perpendicular to the grain line so you don't split the wood ! The advantage this does have though is that it is almost impossible for the gate to come apart !

Personally, when I build gates, I use ring shank nails, quick and easy to use, plus the nail heads don't have a shoulder like a screw head which can cause splitting in the timber.

Always look at the gate itself and see how it is made, usually ring nails from a nail gun on most gates, however there are many types of gates, so experience is key. I can teach you but I have to charge.lol.