Make sure you read the units. My tag is labelled in Kg (Kilograms), if it is youll need to convert that to pounds.
Also, one some cars the weights are written on a metal tag inside the engine compartment. Pop the hood and look for a tag on the right next to the left hood hinge. I think on Nissans this tag only tells you what engine model and transmission model you have though.
If you still wanna know maybe try one of those Semi truck weighing scales. I dont know if it would work but you could try. Go at a time when they arent very busy and ask if they could weight your vehcile.