I think you may be worrying for nothing. Two hours and 23 minutes is probably enough time. Who knows, the PBI departure might be delayed. I admit I don't fly into/out of EWR a lot, but I have rarely experienced a delayed arrival there, whereas I have had numerous delayed departures.
Thanks for the reassurance, RNE. I'm not too worried about it but I can just imagine thunderstorms at ORD delaying me into EWR and thus missing the PBI flight.
Bottom line, it sounds like there is nothing I can do now. We'll see what happens!