2009 sentra. A/C quit working. Took to a mechanic, he says there is no power going to the compressor. All fuses and fusible links are working. What next?

IF THE REFRIGERANT IS LOW THERE WON'T BE POWER TO IT BECAUSE THE SYSTEM WILL NOT ALLOW IT TO COME ON TO PROTECT ITSELF. CHECK THAT FIRST.

I'd go with Robert above. It's either low refrigerant or the actual low pressure switch and or wiring is damaged. Cheapest solution is to get a cheap recharge kit with the gauge. Test the pressure in your system, instructions in the kit. If it's low recharge it. If it's good your have to check the switch and repair the issue then recharge it.