Originally Posted by
DannoXYZ
Hmm, something smells fishy here. A properly set-up 8-spd wheel should NOT rub the chain on the spokes. ....
Reread the OP. All the clues are there.
The chain isn't rubbing against the spokes, it's rubbing against the tire. The OP stated that it's a fat bike, and though He didn't say, I suspect that it has fat tires in the 3"+ width range. That would bring the side of the tire out beyond the fight side hub flange and into the chain's way.