Why use the lock nut at all? The valve isn't going anywhere if the tire is inflated.
Usually the nut's purpose is either to prevent the stem from getting pushed into the rim as the air chuck is being forced on, or even more usefully to prevent the stem from rattling in the hole in the rim.
I sometimes use shrink tubing on the stem to get rid of the rattling, since I'll try anything to avoid having to use the stupid nuts. Some use tape.
Another thing is that I think it's high time that these long, heavy valve stems were made of plastic instead of brass.
It wasn't an issue in the olde days when the stems were all 32mm, when the nuts weren't needed either.