I've had success using an electric grinder and a lot of patience with our JRT who hates her nails being cut and would growl at anyone who tried.
Get the grinder and a pot of treats.
Show her the grinder, give her a treat.
Repeat, repeat repeat.
Then show her the grinder, turn it on, straight off, treat.
Repeat.
Over several sessions, several days, several weeks slowly build her up to looking the grinder, touching it anywhere with a paw, touching it at the right end with a paw, touching it while you reach towards her leg, touching it while you gently hold her leg, touching it while you gently hold her paw, while you hold a nail, while you apply a tiny bit of pressure to the nail against the grinder.
And so on.
Do it in very tiny baby steps. Never rush her. If she doesn't look thrilled to see the grinder because she knows treats are coming then you're going too fast for her and back it off a bit.
Our JRT will now wait while you grind a nail for about 10 seconds before wanting payment in the form of a treat. She'll repeat that for as long as you have treats. It took me about 2 months of a minute or so a day to get her to that stage, but worth it.