UPDATE:
I did it. I did it myself. I am a little handy.
My car has about 12K miles, 1 year old, so decided to do it at one year. More on that later.
So here we go.......I bought a Denso Cabin Air Filter from Amazon (Denso 453-6031), $10.30. A whole lot cheaper than the Nissan part. By the way, when I removed the old filter and compared the two side by side they looked identical, so maybe Denso makes the filter for Nissan.
I watched many videos and certainly wanted to do the job without removing the glove box. So I first removed the piece under the glove box. This was easy it just has a few clamps. You wiggle and pull down on it and it comes loose.
With the door in the glove box open and removed the piece under the glove box, I still could not see the cabin air filter door. I also removed the piece on the side of the inside of the glove box, still could not see the filter door. My guess is that if you have done it before, you might not have to remove the glove box, but you will be doing it blind with just feel for the door. The door is located so far back in the passenger compartment and is on an angle. Who ever designed this, did not think about replacement due to location. So I had to remove the glove box. I was a little nervous about getting it back. Also, the angle of the screws on the bottom of the glove box are at an angle and recessed. You need a philips head screw driver for this. There are about 10 screws in total to remove, they are all the same size, so no worry about mixing them up. When I pulled and dropped the glove box, there is an electrical attachment on the top of the box, probably a light, so that has to be wiggled loose to drop the box.
Now the box is off. At first I could not see the door to the cabin air filter, but with some good lighting I found it. As I said earlier it could not be farther back in the passenger compartment. I was able to use a flat head screw driver and ply the door off gently, did not break the clips which other had warned about. How you get that door off is a challenge. Make sure you take note which end is up and which is down when you put it back. So now the filter was exposed, pulled on the tab, wiggled it a little and out it came, it was snug in there. Put the new one in by bending the front inserted part, pushing it in and bending the rear part to push in. Used the tab to unfold it a little. However, after giggling it around, I ripped the tab off. But no worries, it is very flexible and was able to put my finger in there and move it around and you can pull it out without the tab. The door went back on. Then I put the glove box back with all the screws, and then the piece under the glove box door just snapped on. Wala it was done.
A few after thoughts:
The whole job took me about 30 minutes to do.
If you are prone to getting a stiff neck or have a bad back, don't do it, let the dealer do it and pay the money. There is very little room between pushing the passenger seat back and the space to work. Many awkward positions which put strain on the neck and back.
So after one year, the filter was really not dirty and could have gone much longer, so if you are not in a dusty area, you might think about doing it at a later date than the recommended time in the manual of 15K miles. I live outside on NYC, we don't have dirt roads.
If you are going to do it yourself, buy the filter I mentioned above or another one on the internet that is compatible rather than paying the dealer over $30.