filling holes from nails?

Bigger holes are no problem, even if you don't have all the pro gear.

If it's a hollow-type hole, stuff newspapers in, then put papier-mache on the spot to hold everything in place.  Plaster/spackle over it when dry.  I usually put the papers in damp and gluey.

Non-hollow-type hole... you just don't need the newspapers.

With older houses (lathe and plaster/horsehair mixes, clay walls, etc.)  bonding can be a problem.  Make very fine papier-mache, use it as wet as possible.  Add PVA to the mix.

(Most white glues are PVA.)

I love fixing holes in walls....

Wow, you're an expert at this! I wish my husband or I were good at this sort of thing. As it is, we'll stick to putty and hope we don't end up making matters worse!