Using NLP on both an older (OS12) Mac and a newer M1 (OS14 Mac

I am a one man studio and currently using my old Mac laptop as a designated scanner. If I purchase NLP can I use it on both computers?

Welcome to the forum @LouKern

NLP version 3 requires Lightroom Classic to run. As long as you have LrC on your computer, NLP should work.

You can try NLP for free and I advise you to do that in order to be sure that things work on your devices.

I use NLP on an Intel iMac and a M1 MacBook Air. Both carry LrC 13 on macOS Sonoma though.