O.K so long story short.
Havent changed the iridium plugs or wires for my 2004 frontier truck for 130,000 miles. I believe I hit the point of death with the plugs and wires.
Engine shut down to a few issues.

Its a Nissan, never done mechanical or electrical tune up since the iridium plugs @ 30,000miles. Just changed brakes, and starter. Its a work truck so its about making money, not dumping money into it.

Long story short, cam sensor went off on the San mateo Bridge, shut down the engine completly.

Trouble shooted all aspects of the cam timing.

replaced timing belt that was original, 20 rubber teeth were missing.
replaced distributor/ignition/ cam sensor.

Engine still wont start, starter was replaced 10,000 miles ago.

There is spark.....

So now I am assuming its got to be the plugs and wires I have just ran beyond the mechanical warranty on plugs and wires. Only PITA is changing out that plug closest to the fire wall. Took me 3 hours to get the old one out, and new one in.

Any suggestions on changing out that plug closest to the firewall? Is it faster to remove the intake manifold to get to that plug easier?

Suggestions is much appreciated. VG33e is a PITA opf an engine to work on.

Plugs and /or wires aren't going to make a car not run, when it was running OK a bit earlier.
You mention the old belt was missing teeth. Is the new one on right?
Put a timing light on it while trying to start. Is the timing mark close?
You said it had spark, is it at the plug?
Listen for the injectors to click while you are cranking it over too.
The distributor is the cam sensor. Was that replaced? Did it get put back in right? The ignition timing check will tell you.
As far as that back plug on the drivers side, moving the brake lines helps sometimes, There is a little cutout in the firewall seam to clear a spark plug tool. I I use a swivel spark plug socket with about a 6 inch extension. Take some tape and tape the socket to stay over at its extreme angle on the swivel, and guide it down over the plug. Same thing for putting in the new one. They can be kinda tricky. Once that setup is on the plug, I put a u-joint on top of the 6 inch extension and then and ratchet with a 10-12 inch extension.
Oh, blow all the sand and trash from around the plug before you put any socket down there. That way it wont end up in your engine.

I had a professional service install the timing belt, being limited to my time as a contractor.

They made the excuse that the fuel pump wasn't working, then wanted to frivolously bill for fuel pump, I then towed my truck out of their shop and have been working on it myself trouble shooting what they could of done wrong essentially.

Voltage checked to work at the pump, then opened the sending receiving lines to the tank, both had fuel, pressure also checked OK.

All I can assume at this time is that the timing marks on the crank to the cams are not in correct position. If the cam sensor and crank sensor arent in alignment the engine won't fire. I installed the distributor/cam sensor, all checked out, according to the placement/position of the old distributor. However if they disconnected the distributor and did not install correctly it could all be out of timing.

I haven't used a timing light yet, but at this point it appears I will have to do so.

Another thing I have seen people screw up is the pulley on the balancer. I can't remember offhand if the pulley will unbolt from the balancer on your year truck, but on the earlier ones you can unbolt it and put it back on in 6 different ways, of which only 1 is correct. Otherwise the timing mark wont be in the right place. If they mis-diagnosed a fuel pump who knows what else they did wrong.