How to cut nervous older dog's nails?

We use a nail file instead of clipping. Go to a beauty supply store & get one of those big nail files with a really rough grain. My dog hates having his nails trimmed but he actually likes the attention he gets while getting them filed down. And I don;t have to worry I'll hurt him either.

He's spoilt rotten, is all it is. Most dogs will let go of a "bad experience" unless they've figured out that the OWNER feels bad about it and they take advantage of that weakness. Dogs aren't built to hold onto experiences like humans - it would have had to have been MULTIPLE TRAUMATIC experiences, and that would likely show in other aspects of his behavior (which maybe it does, i don't know your dog so i can't really comment on that.)

And don't tell me that this doesn't happen - as a groomer i see many dogs come in followed by owners who say "oh, since this and that happened he won't let me trim his nails! Be careful, he might bite!" Five minutes later i have the dog on the table, let him throw his fit, then i get the job done without a scratch to me. Owner is baffled, can't do it at home later on, then keeps coming in for me to do it for them. Only explanation is the dog is reacting to something the owner is doing.

Stop drugging him - unless he's totally out (which won't happen unless a vet is present) then drugging just makes him more unpredictable and uncomfortable. I won't touch a drugged dog with a ten foot pole. Find a behaviorist who is willing to show you how to work through his behavioral fits, not cover them up.

Why are you taking medical advice from someone who isn't a veterinarian?

Have someone hold him and feed him high value treats while you clip him. Hide the trimmer until he's comfortable, and only do one paw at a time, to reduce his stress level.