Just bought a Nitro 5, part number NH.Q6ZEK.005. The Acer page for the model mentions the 144hz feature, and says this is possible via LCD Overdrive. Overdrive is not present in the Nitro sense app.
Acer page:
https://www.acer.com/ac/en/GB/content/model/NH.Q6ZEK.005There no obvious reference anywhere in Windows to anything other than 60hz.
The part number and the model code, AN515-43-R5W3, are the same. I appreciate that there are about six thousand different Nitro 5 combinations, and that posts on this forum show people buying the wrong model for 144hz, but as far as I can see this ought to have the feature. It would be great if anyone can point me to how to resolve this 😀