Indeed, that is the OBDII port - standard on all cars that are OBD II compliant.
The OBD II error codes on the NSX only relate to ECU operation. If you have a penchant for a little self abuse, the OBD II cars also have the service check connector which is sort of over to the right along the edge of the foot well and up a bit from the OBD II port. I discovered mine when I had the cover below the glove box off. You can use the service check connector to trigger the display of error codes on things like the TCS and some other stuff. Lots of fun counting blinks and delays on the indicator lights. The service manual kind of implies that on OBD II cars the service check connector can also be used to trigger blinking of the MIL if there are any diagnostic trouble codes. I don't know whether that means you can read the actual code or it just confirms that there are stored codes. Reading multiple stored 4 digit OBD II codes from a blinking light would be an exercise in frustration.