Hi,
You can add a resistor if you want, but you need to know what current the display consumes because you don't want to drop too much voltage through the resistance.? Different 2-line LCD's will consume different current depending on their backlight type.? I imagine the Nexion displays also vary a lot in what they consume.? I would just put a TO-200 heatsink on the regulator and it should be fine with that.? Too much current through a resistor can cause other problems too (e.g. needs to be sized by wattage appropriately)!
73,
Mark.
