First thing to check is belt tension on both belt.

 

Most of the time that's a loose belt. Can also be caused by a tensioner hanging up on a serpentine arrangement, but a simple loose belt is usually the cause.

 

I have the same issue. were you able to get it fixed? My alternator was recently replaced (about a month ago). I wonder if it's related to that.

 

Check belt tension.

 

A bad or failing pulley bearing could be the cause of the noise.

Since you had your belt changed a year ago there is a possibility that the belt was installed with too much tension on the tension-er, which will ruin the pulley bearing overtime.

It is very important to use a belt tension gauge when installing the belt on the Murano due to it not having a self-adjuster to avoid messing up the pulley in the long run from belts installed too tight.