Yes, ATF or Marvel Mystery Oil as can Sea Foam can quieten a lifter. It’s worth a few bucks to see if it will work or not.
If the lifter does not shut up it’s possible that the lifter (sometimes called a hydraulic lash adjuster) may be damaged on the tip by infrequent oil changes. In a case like that the only fix is to replace it; and this means the full set.
At that point the cam lobes should also be carefully inspected as chronic valve lifter tapping can damage the lobe; or lobes.
And hopefully the rocker roller bearings are not beaten… 