Cook ½ cup uncooked quinoa according to package directions and set aside.
Meanwhile, melt 1 tablespoon unsalted butter in a large, oven-safe skillet over medium heat. Add ⅓ cup finely chopped red bell pepper, 1 cup roughly chopped artichoke hearts, and 2 cups roughly chopped fresh spinach. Cook for a few minutes until the spinach is wilted.
Stir in 2 tablespoons all-purpose flour and cook for a few minutes, stirring frequently. Gradually whisk in 1¾ cups milk. Add 1 teaspoon chicken bouillon powder, ¾ teaspoon Italian seasoning, ¾ teaspoon onion powder, ½ teaspoon garlic powder, and black pepper to taste. Stir until well combined.
Cook until thickened and creamy, stirring occasionally. Stir in ¼ cup plain Greek yogurt, 1½ to 2 cups shredded cooked chicken, and ¾ cup shredded Italian cheese blend. Mix well until combined and the cheese is melted.
Mix together ½ cup Panko bread crumbs, ½ teaspoon dried parsley, ½ teaspoon garlic seasoning, and 1 tablespoon melted butter. Sprinkle the breadcrumb mixture on top.
Place in the oven and broil for a few minutes or until the breadcrumbs are toasted. Remove from oven and serve.
