I'll second that vote for wheel bearing. When they start to go, they sound like a rock crusher or bulldozer/grader/tank tracks. The wheel bearings on these Xterra's are absolute garbage. I had the front right one replaced under warranty on our '08 @50k miles. Just replaced the other front left one today @ 106k miles. You should be able to get it replaced for around $300-400 tops. Dealers will want north of $500 though. The part is under $200. This one was practically disintegrated. I'll say it one more time, absolute garbage. I know wheel bearings go once in a while, but not like that and not that often. Oh, both rear wheel bearings have also been replaced, thank god under warranty. Our X required a whole new rear axle assembly because of failed bearings.I vote wheel bearing.
Put the front tires on the rear to rule out the tires.
While you are at it, take a caliper off so the hub can spin freely and listen to the bearings. also check them for play.
I feel that the CE light is maybe unrelated to the noise.
Yeah this is what I was referring to when I mentioned checking the wheels for security.Just mention it to them and they can check the bearings for play when they have the truck in the air. Maybe ask to go out and spin the wheel and/or hub while they have it up just so YOU know for sure.