Compression test is something totally different. A valve adjustment may be necessary on your engine but if you don't do it you can keep driving it no problem, just that they'll make more noise and you might theoretically get a bit of a decrease in power when you mash the pedal. The problem with shim and bucket is that they're simple and rarely do lifters themselves fail, but that clearances are different when cold and warm, so even when the clearance is within specification, you'll still get lifter tick at cold startup. Hydraulic lifters are self adjusting, they are essentially 2 "buckets" that slide within each other, that fill with engine oil, and a spring inside to make them self adjusting. Liquids are incompressible, so the hydraulic lifter is supposed to behave like a solid piece of metal when full of oil.
Valve adjustment is normal maintenance, problem is alot of Nissan motors use shim and bucket, which is harder to adjust than a roller rocker setup like some Honda motors use, all you have to do to adjust a roller rocker setup is use a feeler gauge that is the proper thickness for the desired clearance, and tighten your rocker down on it.