I suspect you are using a MODIFIED SINE WAVE INVERTER to give you 120VAC to run your laptop computer charging brick. This will eventually burn up your transformer brick... Transformers really like to have PURE SINE WAVES...
The only other way to overheat the laptop transformer brick is to PULL TO MUCH CURRENT trying to charge your LAPTOP. PERHAPS the LAPTOP BATTERY is going bad on you... Just be sure you are using the correct transformer brick for your LAPTOP.
My DELL LAPTOP bricks get warm running on good 120VAC Shore Power but never HOT... When you are saying HOT I am thinking too hot to touch????
Roy Ken