Preheat oven to 375°F (190°C). Grease a 9x13 inch baking dish. In a medium bowl, toss chicken pieces with olive oil, garlic powder, salt, and pepper until evenly coated.

Heat a large skillet over medium-high heat. Add chicken in a single layer and cook for 7-9 minutes total, stirring occasionally, until golden brown and cooked through. Transfer to a plate and set aside.

In the same skillet, add the thawed and drained spinach and chopped artichoke hearts. Cook for 2-3 minutes until heated through and any remaining moisture evaporates. If liquid pools, cook an additional 1-2 minutes.

In a large mixing bowl, beat the cream cheese until smooth. Add Greek yogurt, Parmesan cheese, 1/2 cup of mozzarella cheese, mayonnaise, minced garlic, and chicken broth. Mix until well combined and creamy.

Add the cooked chicken, spinach, and artichokes to the cream cheese mixture. Fold gently until everything is well coated. Transfer the mixture to the prepared baking dish and spread evenly.

Top with the remaining 1/2 cup of mozzarella cheese. Bake uncovered for 20-25 minutes, until bubbly around the edges and the cheese is golden brown. Let rest for 5 minutes before serving.