The .nng file extension is most commonly used by the Pioneer AVIC navigation unit. These files contain the serial number assigned to the associated navigation device. The NNG file is used to synchronize the Pioneer AVIC unit with the Poicon Speedcam service.
Unfortunately we have not received enough suggestions for software that can open NNG files yet.
File.org aims to be the go-to resource for file type- and related software information. We spend countless hours researching various file formats and software that can open, convert, create or otherwise work with those files.
If you have additional information about the NNG file format or software that uses files with the NNG suffix, please do get in touch - we would love hearing from you.