Preheat the oven to 375°F (190°C).
In a small bowl, mix together the olive oil, garlic powder, salt, black pepper, and Italian seasoning.
Place the chicken breasts in a baking dish and brush both sides with the olive oil mixture.
Spread the basil pesto evenly over the top of each chicken breast.
Sprinkle the shredded mozzarella cheese on top of the pesto-covered chicken.
Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C).
If desired, broil for an additional 2-3 minutes to brown the cheese slightly.
Remove from the oven and let rest for 5 minutes before serving. Garnish with fresh basil leaves if desired.