Why are my Nissan Armada interior lights not working?

First, if You mean the dome light on Your Nissan Armada isn't working, the simple thing is to make sure the switch wasn't accidentally turned off. Additionally, if there's a failed sensor in the door, it's not triggering that You've opened it and require illumination; that's pretty easy to check, too. After those, You're going to want to look at the fuse; on the inside, in the fuse box on the passenger side, You're going to want to check fuses 19 and 22, as well as fuse 55 in the fuse box in the engine compartment. While You're there, it doesn't hurt to glance at the other fuses, but those are the important ones. It's unlikely, but possible, to have multiple bulbs fail at the same time; also, give a look over at the wiring. If You've checked all of that, much more rarely You can have a failure of the engine control module, that's failing to signal the lights to turn on.