[Update] I am sitting at Nissan to get a bulb replaced, rear drivers side.

[bucolic_frolic]

6. Here's the architecture

On a 2007 Nissan Versa hatchback, the rear lightbulbs are accessed by removing the entire tail light housing assembly from the outside, not from inside the hatch. You must open the hatch, remove two 10mm nuts hidden behind plastic covers in the interior trim, and pull the assembly backward.
Key Steps for Replacement:
Access Inside: Open the hatchback and pry off the two small circular or rectangular plastic panels on the interior trim behind the taillight.
Remove Housing: Remove the two 10mm nuts found behind these panels.
Release Assembly: Carefully pull the entire light assembly straight back from the car. It is held by a plastic guide pin on the side; you may need to firmly tap it or pull steadily to release it.
Replace Bulb: Twist the bulb socket counterclockwise to remove it from the assembly, replace the bulb, and reassemble in reverse.

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As for brittle plastic. I dunno. Plastic can get brittle with age and heat and sun, so you have to go carefully.

If they break the lens or housing, get all the pieces to take home. Glue, epoxy, pins ... I once broke off the turning signal stem on a Honda. Incredibly it was plastic. I think a national muffler chain broke it on the test drive, but I digress. I took the shaft and drilled a hole in each corner ... we're talking 3/16" of plastic. Clamped the shaft on the broken stem, then blow torched the pins and rammed them in. Sanded off the excess. It's stronger than original. Because I couldn't buy the part anywhere, once the warehouses are empty, no more. Scarcity.