Treats! Your approach will be how Nelly is most comfortable - there are a couple of videos online using a head on approach or a behind approach...both secure the bully's body from backing up. TREATS!
We recently had to give eye drops to Castor, who is quite cooperative, and I used what would probably be a 'behind approach' with one hand holding his chin and the other to administer the drops. What was difficult some days was to make him open his eye! Good luck!
Yes, praise love treats, those all help to get the routine established. Never try it when you're irritated, take a deep breath and have patience, talk sweetly and kindly and pretty soon it will just be something you do real quick because you will both be so used to it being done. If for some reason the first few times do not go well are you try to pin them down or have somebody else hold him while you put it in sometimes these approaches can scare them and make them want to run and hide. So a positive experience is very important.
use a harness. Once in the harness...wrap your arm thru it to hold them and keep your hand free to administer the drops. I posted a photo in another thread asking the same question.
You've been given great advice and suggestions. When Blossom had her cherry eye surgery, I had to put eye drops in her eyes and I sat on the floor, and had her between my legs with her back to me, and I just held her chin in my hand, and had her head rest on my chest, and I pulled the eyelid down and administered the drops in her eye. She didn't mind so it was easy. I don't have experience with trying to do it when they are fighting you. I do have that problem with Dozer though when I have to put ear cleaner in his ears. He runs away as soon as he sees the bottle. Lol.