Welcome to Ozdat
A Nissan L-series MAY bolt in, but if it does I am not sure what the situation with your gearbox would be. The one from your truck probably wouldn't bolt up and if it is column shift then finding an L-series gearbox to suit might be a challenge. As well as this, finding a good running L-series isn't as easy now as it used to be.
Had you considered rebuilding your existing engine? Doing that might be a cheaper and easier option. Neither option I have mentioned will be much, if any power improvement, plus both engines are now at the age where they aren't especially easy or cheap to find in good running order. Rebuilding yours would give you the peace of mind that everything is mechanically sound.
Feel free to post some pictures or start a build thread too