Devil 49: I have to agree with Shy Torque. It depends on the flight manual.
But to my way of thinking, a chip light can hardly be compared to a sick passenger or weather diversion. Neither of these is an indication of possible catastrophic failure. It comes down to how willing you are to bet your life that the indication is minor. I dont bet my life, no matter how good the odds are. I throw the PAN out if there are no secondaries because they may appear on the way down when I am too busy handling the secondaries/failure to remember ATC. Or it the failure may appear on short finals when I have no time to react. At least someone is alerted. Either way, I will have a long time on the ground to cancel the call.
By the way, doesn't PAN mean you do, or you might need assistance, whilst MAYDAY is in need of immediate assistance? Thus for a chip with no secondaries I call PAN: i.e. watch over me in case I dont land safely. For secondaries (except one engine in a twin) a MAYDAY: i.e. It's serious, I may have a catastrophic failure, so start getting the help organised.