Prep the oven and pan. Heat the oven to 400°F (200°C).
Lightly spray a 9x13-inch baking dish with olive oil.
Season the chicken. Pat the chicken dry. Drizzle with olive oil and sprinkle with salt, pepper, garlic powder, onion powder, and Italian seasoning. Lay the pieces in a single layer in the baking dish.
Make the creamy garlic sauce. In a mixing bowl, whisk together Greek yogurt, light cream cheese, chicken broth, milk, Dijon, minced garlic, and Parmesan.
Stir until smooth. Taste and adjust salt if needed.
Add greens for color and nutrients. Scatter the chopped spinach over the chicken. It will wilt down in the oven.
Pour and top. Pour the garlic sauce evenly over the chicken.
Sprinkle mozzarella and a little extra Parmesan on top for a golden, cheesy crust.
Bake until juicy. Bake uncovered for 22–28 minutes, depending on thickness. The chicken is done when the internal temperature reaches 165°F (74°C) and the sauce is bubbling.
Finish with brightness. Remove from the oven and rest for 5 minutes. Squeeze lemon juice over the top and add chopped parsley.
This wakes up the creamy flavors.
Serve. Spoon the sauce over the chicken and plate with your favorite sides—steamed green beans, roasted broccoli, or a scoop of brown rice or quinoa.