I recall reading somewhere that the procedure for replacing the cabin air filter on a cube is identical to that of the Versa cabin air filter replacement procedure. I have yet to swap out the filter on my cube but here's a write-up on replacing the cabin air filter on a Versa:
--Tools and parts needed--
Cabin Air Filter- OEM part # B7891-1FC0A at http://www.nissanpartszone.com/parts...891-1fc0a.html
1. Open the glove box door and remove the two screws at the top and three at the bottom in the hinge area, using the Phillips screwdriver. Pull the glove box out far enough to disconnect the glove box light harness connector directly behind the box.
2. Pull the glove box out. This installation uses spring blind clamp nuts. These are pieces of metal bent in half with a hole on one end for the screw and a nut on the other. They are the type the are pressed over an existing hole in metal or plastic and held in place by their clamping action. When the glove box is removed some of these may not be very tight and may fall off. Make sure to pick them up.
3. Look straight back behind the glove box opening and you can see the rectangular plastic door above the blower motor. You must lift the plastic tab on the right to release the door. Lift up a little on the door, which is part of the filter, and pull the filter out.
4. Push the new filter in until the tab on the door snaps. Install the blind nuts if any fell off. If they did, look at the five holes in the plastic part of the dash to see which ones fell off. If they fell off they are loose, so pick the fastener up and squeeze it with the needle nose pliers. This will make it a tighter fit over the hole. Push them over the holes from where they fell off.
5. Hold the glove box up and connect the light electrical plug. Insert the glove box and five Phillips screws and tighten them.
Again, I can only speculate that this write-up can apply to the cube's cabin air filter replacement procedure. Hope this at least helps you out somewhat!