My 2015 Nissan Pathfinder Platinum does not heat very well. Is this common

Hello, no, it is not common for a vehicle to not heat very well. Sounds like your "local mechanic" isn't equipped or skilled sufficiently to share more about your vehicle? Yes, a dealership is an option, but there may be other repair shops near you. By the way, $150 an hour is not an abnormal cost to spend for diagnosis and repair in 2022. I'm sorry that you have a concern and a vehicle that you'll have to spend money on, but most shops are going to have a comparable labor rate. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops