Lettuce nudi MAY eat bryopsis, but IME, you'll be disappointed. Water changes, skimming, kalk drip, and manual ripping are the only ways I've found.
You can pull more bryopsis out of your tank in 30 seconds than a lettuce nudi will remove in a week - IF it even eats it.
Anyway, if you want one, they had a few in at Old Orchard on Thursday. I'm sure you can find one locally.