In a large skillet, heat olive oil over medium heat. Season the chicken breasts with salt, pepper, onion powder, and garlic powder before searing them in the skillet for about 5 minutes on each side until golden brown. They do not need to be fully cooked at this stage. Remove from skillet and set aside.
In a mixing bowl, combine cream cheese, sour cream, mozzarella cheese, Parmesan cheese, minced garlic, chopped spinach, and artichoke hearts. Mix until everything is well incorporated, and season with a pinch of salt and pepper to taste.
In a baking dish, lay the partially cooked chicken breasts down. Spread the creamy spinach and artichoke mixture generously over the top of each chicken breast, ensuring they are fully covered.
Bake in the preheated oven for 25-30 minutes or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C). The top should be golden and bubbly.
Once removed from the oven, let rest for 5 minutes. Garnish with freshly chopped parsley if desired before serving.