What causes a loud chirping engine noise and how much to fix it? on 2008 Nissan Xterra

Chirping started while driving about 45mph, engine warmed up, all gauges appeared in normal range. This was the first time it happened, I did not hear it when I stopped and backed up into my driveway. It chipped for approx 2 miles of driving.

Asked by for the 2008 Nissan Xterra
I would be just guessing to give you an answer, just like you are guessing where the sound is coming from. The chirping noise needs to be verified before the cost can be given.