The name of Chios has been lost from this inscription, but it is a reasonable assumption that it refers to the sea-battle in which Attalos and his Rhodian allies inflicted serious losses on the Macedonian fleet ( Polyb_16.2-10 ).
[King] Attalos dedicated this to [Zeus] and [Athena] Nikephoros, from the sea-battle [against Philippos] and the Macedonians [(?) near Chios].
Attalus' home page | 15.11.16 | Any comments?