Not all angels nip, it's really a crapshoot. I've got five angels in all (white-tailed pygmy, cherub pygmy, flame, coral beauty and flagfin), none of which have touched my corals so far. That said, I bought them all knowing the possibility exists and while I won't under any circumstances give up these gorgeous fish, I'm willing to remove the corals if needed.
Lemonpeels have a reputation for nipping, most people give 50/50 odds - if you add corals, I'd try things he may be less likely to go for like GSP, shrooms or leathers and avoid those more often eaten by angels like Xenia, brains, candycane etc. I had a halfblack who loved euphyllia corals so maybe stay away from those as well.