The standard procedure for them is to replace the pump first and then look at other solutions. I'd do things a little different.
1) Check the primer bulb. Squeeze it until it becomes firm - it should take no more than 5 squeezes. If there's more, you have a leak in the fuel system. Check the hoses for cracks, check the water sensor in the fuel filter is clicked all the way in so that it lines up with the black knob above.
2) Undo and redo all of the electrical connectors around the fuel pump. Some people pressure wash the engine (my own dealer does this!) and that can cause bits of dirt to get into the electrical contacts. Not a good thing, but easy enough to remedy.
3) If fuel is getting to the filter (step 1), then crank the engine a couple of times. If it doesn't fire, remove a glow plug and check to see if it's wet. If it's wet, you're getting fuel, and have a different problem.
4) If you're getting fuel in, you may have an air restriction. Temporarily remove the air filter and try again, watching the air hoses to see if any of them collapse. There's one between the air filter and the turbo, one from the turbo baffles up on top of the engine near the turbo down to the front where it connects to the intercooler, and one from the intercooler to the intake manifold.
5) If the engine kicks but dies immediately, block the EGR (if yours has this). Do this by removing the two 12mm bolts from the gold pipe that comes around the front of the motor and carefully slip out the gasket. Make a copy of this gasket with 1mm stainless steel and only make the bolt holes, do NOT make the large hole in the centre. Reinstall with the gasket and use some gasket cement to make sure it's a good seal. EGR may be flooding the intake preventing enough air from entering the combustion chamber. If you don't have EGR, you shouldn't experience this sort of fault.
6) If the engine runs but doesn't like going past 2,000rpm and lacks power but doesn't show the Check Engine Light, you may have a dirty/damaged SCV (component on the fuel pump). This costs about twice from Nissan as it does from eBay or aftermarket. I have an aftermarket one in my car and it has not given me trouble in years.
Hope that helps.