Preheat your oven to 375°F (190°C) and lightly grease a small baking dish.
Cook the whole wheat penne in a pot of boiling salted water until al dente, then drain and set aside.
While the pasta cooks, cut the chicken breast into bite-sized pieces and season with salt and pepper.
Heat olive oil in a skillet over medium heat and sauté the chicken until browned and cooked through, about 5-7 minutes.
Add the minced garlic to the skillet and cook for 1 minute until fragrant.
In a small bowl, whisk together the Greek yogurt, chicken broth, dried oregano, and chopped sun-dried tomatoes to create the sauce.
In the baking dish, combine the cooked pasta, sautéed chicken, fresh spinach, and the yogurt sauce, tossing until the spinach begins to wilt.
Top the mixture evenly with shredded parmesan cheese.
Bake for 15 minutes until the sauce is bubbling and the cheese is melted and golden.
Remove from the oven and let rest for 5 minutes before serving.