Nikon stores the shutter actuation count (an unsigned 32-bit integer) in the EXIF Maker Notes, with a tag name of "ShutterCount". Thus, you can shoot a frame and read the shuttercount value from the resulting image file using any tool that will show the Maker Notes. For example:
exiftool -shuttercount file
where "file" is the name of an image file that still has the EXIF information in it.
(ExifTool's author, Phil Harvey, maintains a web page for it, ExifTool by Phil Harvey