Mix together mayo and pesto in a small bowl and set aside.
Lightly butter one side of each slice of bread. Place buttered side down on a skillet. Smear Everything Spread on the bread. Layer on some chicken and mozzarella cheese.
One the other slice of bread, spread the pesto mayo on the opposite side of the buttered end. Place pesto end on top of mozzarella.
Heat up skillet and then place the bottom of a heavy skillet on top of the sandwich, pressing it down (can also use a panini press). Flip sandwich when the bottom is golden brown.
Cut in half and serve. Enjoy!