Preheat oven to 350ºF. Lightly coat the bottom of a small baking dish with cooking spray and place chicken breasts inside.
Spread 1 tablespoon of pesto over each chicken breast and let the chicken rest and marinate in the pesto for a few minutes while the oven heats.
When the oven is hot, bake the chicken uncovered for 25 minutes.
Remove from oven and sprinkle 1/3 cup mozzarella cheese over top and return to the oven for 5 more minutes.
Note: this recipe is written for two because that’s all my family needs at a time right now, but it’s super duper simple to double, triple, or quadruple it. The only thing you need to change is maybe adding a little more cook time to account for more chicken in the pan.