Typically the reason they nip or bite is because they are highly territorial. Most clowns pick a spot and really dont leave it all that much, if ever. And if they are hosting with a nem or coral that is there space and they are guarding it.
Another method along the same lines using a net or something like that to persuade them to hide..i use a glass scraper/water stirring stick to keep them away when I feed the corals..guess it depends on how brave yours is lol
That's what I do just let the net sit in the tank and she will stay in her anemone but sometimes she finds away to get around the net just to nip at me