Cant get gas through either jet

Does it try to start if you spray starting fluid into the throttle body ?
Are you getting power and ground pulse to the injectors ?

Fuel pump could be bad. Newer car? Could be security. Year make and model helps.

Could be clogged throttle. Get a throttle spray and clean the the throttle body and the jets.

Your throttle body should have an adjustment screw on the linkage...this usually indicates there is another problem causing a bad idle...try air filter, clean fuel injectors with gas additive and add liquid "heet" to gas tank to dissolve bad gas (water) in your tank...then try spray cleaning the throttle body too. Find the cause, instead of trying to adjust...:)

Are you sure it is a carburetor and not throttle body injection? They do look similar.
If it is a carburetor, there would not be a regulator. The fuel pump will either be a mechanical pump mounted on the engine, or a low volume electric pump in the gas line from gas tank to the engine.
If it is throttle body injection (TBI), yes, there is a fuel pressure regulator, probably located near the throttle body. It will have gas lines connected to it (one line will be a return line back to the gas tank) and a vacuum line. The fuel pressure on TBI systems is not as high as multi point injection, usually around 20 psi. You would have to check the specific pressure requirement for your pathfinder.

Take off the air cleaner cover and look at top of unit. A carburetor should have a choke plate right at top of the carb throat. However some Nissans by '88 had a carburetor without a choke-it used an enricher jet controlled by the ecu for added fuel when starting.. On a TBI, looking down at the unit where the air goes in, you will see one or two injectors with a wiring harness connected to them-each injector will have two wires connected to it.
If still unsure, check engine designation on the under hood label. Carbureted engines will have a s letter designation, injected engines will have letter i. To explain: my '87 Sentra is carbureted, so engine designation is E16s, some same engines were injected, so their designation is E16i.

check all fuses under left dash if that doesn't work check to c if you are getting power on the injector plugs if you are getting power then go to a junk yard and get a throttle body

Your model should be a throttle body injected engine.
So no float and no jets like a carb.
Have you checked fuel pressure before and after cranking ?
Are the injectors spraying fuel when you crank it ?
If not, do you have power and a ground signal for the injectors ?

on cool motor, remove fuel line to throttle body, turn switch to accessory position fuel should flow freely. no flow check filter located on frame rail. or defective fuel pump. pressure should be(if checked with good guage)45-55 psi. if all checks out throttle body jet clogged with gunk or you have broken-damaged throttle body wires. all of this i have found on 2.8 liter engines.-------jawstech goodluck hope this helps.

Throttle body injection? replace the injectors. First check for power to them. 12 volts from one of the wires with key on

Depending on year. I would check cheap things first. First check lines for leaks. Replace Fuel Filter with new one. If fuel injected? have fuel injectors checked. If Carberator? Check for Vacuum leaks around the throttle body, Check Intake, and carb itself for leaks. Now i would go ahead and check the Fuel pump. If Injectors? Have the fuel pressure checked. If Carb? Try a new Pump.
You didn't specify what year and model or what engine. So It's kinda hrd to figure it out. but i gave you the basics for all engines.