I have a small patch of zoas, some SPS, the only thing I have close to an LPS are my candy canes, so far my potters is a model citizen. Hes actually my second one, and both were model citizens.
I do see him nip at rocks and in zoa patches every now and then but it appears to me that he's looking for algae or other stuff rather than the corals. When he nips, he never hits the same patch of zoas repeatedly and never enough to make the zoas close up permanently. Seeing him nip constantly at my front glass right above the sand bed where algae is gathering kinda reaffirms my belief that he's looking for algae and not corals. Of course your mileage may vary... but with enough rocks and stuff to graze on, you should be okay.