[KtG]

A/C lines dont just clog. Sealed, isolated systems. So the only way for a clog to form is to introduce a contaminant (like sealant) or have the compressor puke its guts into the line.

The only other possibility is the TXV failed. rare, but it happens. Not hard to diagnose either, but it would look like a clog to someone who only knows o-tube systems.

 

[KtG]

There is a small screen located in one of the coolant lines in every AC system. It is to pick up debris that can damage the compressor. Changing it requires opening and draining the system of coolant.

Go to an AC shop, not the dealer. Save money.

A stock Nissan system has no screens. I usually install them when I replace a compressor, but they are not in there from the factory. Nissan also uses a TXV, so there is no orifice tube screen either.

But yes, take it to a shop. 'Has freon' is not a proper diagnosis, because what matters is having the correct amount of refrigerant. only way to know that for sure is to recover what is in there and then recharge. Working off pressures alone still leaves a grey area.