Favorite Method For Filling Nail Holes On Trim?

Paintable caulk, wet-wipe smooth and clean up is quick and easy, also.

Depending on the size of the nail head/hole, sometimes a slight dimple will result after the first filling/wipe smooth. Subsequent quick wipes, right & left- up & down, usually solves the dimple issue.

Sonny

Spackle, easy to remove the excess after it dries.

For commercial touch up and repair work were time is money we'd use Patch-N-Paint spackle. Used to get it locally from Sherwin Williams, but one of the box stores had a comparable product. When I was contracting I'd always get it from Sherwin Williams because they also did a better job of paint matching. I'd just drop off a paint sample, and come back later to pick up everything I needed.

This stuff? No sanding or priming. That I like.

I have a tube of DAP DryDex (goes on pink, turns white when ready to sand)

Just for fun I tried "sanding" it (lightly) with a wet paper towel. It cleaned the excess off the painted trim just fine, but I can feel a slight dimple on the nail holes. I'll try normal sanding tomorrow to see if it was the wet paper towel or my application method (finger) that caused the dimple. I know, I know, use a putty knife. ;-)

This in-depth review sings the praises of 3M Patch-Plus-Primer. Not based on the inclusion of the primer, mostly on the usability of the product.

Sure that will work too. I prefer the pink shackle, it is pink until it is dried and then it turns white. Most all are very soft/easy to sand, unlike wood putty. And you can paint over all. A swipe or two with a sanding sponge is all you should need to do before painting.