It's a Positive Crankcase Ventilation (PCV) valve. Not sure which engine you have or I would have given you a couple of part numbers.
Well, guess I can give you both:
Standard Motor Products V207
Standard Motor Products V236
Those are the rotating joints holding the top of the McPherson struts which contain the shock absorber and spring for the front suspension allowing the steering to work.
Simply there is a bearing in there inside the rubber mount to dampen vibrations.
My guess would be that they are electrically operated solenoid valves for shutting off the diesel when the ignition is off. Looks a bit like this in a rubber mount -
Taken from - https://12voltfuelvalves.com/product/12-volt-multi-fuel-shut-off-solenoid-valve/
Oh, I was wrong.
It appears to be an equivalent to part 17 in the inset exploded diagram.
Didn't make the connection at first, because it looks quite different in shape and style to the diagram's "circlip", but this C-shaped open ring is a retaining clip / securing ring.
It keeps the axle shaft from escaping the outer joint.
I don't know for sure, but it might be. If you look at the models which can use this part, there's a ton of them. It was used on a wide variety of VW/Audi lines from about 2000-2020. If you don't see the clip as you pulled your old one apart and it isn't in the diagram, I would not worry about it. Manufacturers often include a small part and even duplicate ...
It is possible to work out the year of manufacture of that part but not the specific vehicle.
Even getting the year and possibly week of manufacture would not be easy.
So, you are unlikely to be able to find the vehicle.
You can ask the at the parts counter of a Nissan dealer.
You might also have success searching for the part on eBay. By specifying the model and year of the vehicle, eBay will return a listing of available parts, and many of those listings will contain Nissan's part number.
EDIT: The answer to this question contains another very good tactic for finding the ...
Judging by the similarity to my Octavia's intake system (which is also a TSI engine) it is a simple cover that redirects intake air flow from the open parts around the bottom of the housing back down through the round opening in the centre and though the pipe into the the air cleaner. Mine comes via a pipe off of the the left hand side of the missing cover ...
The part you have circled in the first image is the Vapor Canister Purge Valve / Solenoid:
I found it here on RockAuto.com (NOTE: I have no affiliation with RockAuto, just showing the information).
This is an emissions part, but is separate from the EGR. It should be plumbed from the fuel tank (or charcoal canister) to the intake manifold.