Have you tried wrapping him in a towel? This is what I do to mine, and they're not even mean bunnies, I do it to keep them from wriggling about
Obviously dont wrap him too tightly but tight enough to stop him moving about.
If you have someone to help then ever better. They can hold bunny in the towel and you then have 2 free hands to hold a paw and trim the nails.
I'd recommend enlisting the help of someone calm - one of you hold bunny, one of you clip.
If bunny gets stressed, just do one paw a day. Give him a treat straight after.
Also, I would use nail clipper with a guard on so you can't overclip. Just in case bunny jumps as you clip. It's the worst feeling in the world when you overclip and make bun's nail bleed.
Also, I would recommend doing it at ground level, to avoid falls and injuries.
If you have to do it by yourself, I would say kneel down and contain bun between your thighs (the things we do), either head in or out, depending on what paw you are doing. Obviously, if bun is a nipper, protect yourself with a nice thick towel.
I enlist the help of my dad.
We wrap the bunny in a towel and sit it on its bum on my dads lap, not on its back, but with its back resting up against my dad with feet sticking out, bum tucked under, if that makes sence?
I then get each claw done, put on floor, towel off, and reapeat another 6 times....