Pat the chicken breasts dry with paper towels. Season both sides with 1/4 teaspoon salt, 1/8 teaspoon black pepper, garlic powder, and dried Italian seasoning.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken breasts to the skillet and cook for 5-6 minutes on one side without moving them, until golden brown.
Flip the chicken breasts and cook for another 5-6 minutes, or until the internal temperature reaches 165°F (75°C). Remove the chicken from the skillet and cover loosely with foil to rest.
In the same skillet, reduce heat to medium and add the remaining 1 tablespoon olive oil and the butter.
Add the minced garlic and sauté for 30 seconds until fragrant.
Add the sliced zucchini, season with the remaining 1/4 teaspoon salt and 1/8 teaspoon black pepper, and cook for 5-7 minutes, stirring occasionally, until the zucchini is tender and slightly browned.
Return the chicken breasts to the skillet to warm for 1-2 minutes with the zucchini.
Sprinkle chopped fresh parsley over the chicken and zucchini before serving.