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 olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken breasts to the skillet and cook for 6-7 minutes on one side without moving them, until golden brown.
Flip the chicken breasts and cook for another 6-7 minutes, or until the internal temperature reaches 165°F (74°C). Remove chicken from the skillet and let rest on a plate, covered loosely with foil.
In the same skillet, reduce heat to medium and add the remaining 1 tablespoon olive oil and 1 tablespoon butter.
Add the minced garlic and sauté for 30 seconds until fragrant.
Add the sliced zucchini, season with remaining 1/4 teaspoon salt and 1/8 teaspoon black pepper, and sauté for 4-5 minutes, stirring occasionally, until zucchini is tender but still slightly crisp.
Remove the skillet from heat and stir in chopped fresh parsley.
Serve the chicken breasts sliced or whole alongside the sautéed zucchini.