Lenny, dimmer switches, even good ones under a moderate load, are known to dissipate quite a bit of heat like this.

You’re pushing it’s load rating with 17X60, but even if you replace it with a switch of higher rating you should not be surprised by noting some heat at the switch.

If this light is used minimally I’d not get overly concerned, but I would consider trying 40-50 watt bulbs instead, or if your chandelier has staggered bulb heights, try using lower watt bulbs on one tier to bring you a little below the rating.

Even when thousands get away with it safely every day, it’s always best to stick within the ratings so that you don’t become that “one-in-a-million”.

Good Luck- David