Preheat oven to 375 degrees Fahrenheit.
Boil high protein pasta in salted water for 2 minutes less than package directions until al dente.
In a large mixing bowl, whisk together Greek yogurt, chicken broth, Parmesan cheese, minced garlic, onion powder, salt, and pepper until smooth.
Fold the cooked diced chicken and chopped spinach into the sauce mixture.
Drain the pasta and combine it with the chicken and sauce mixture, tossing to coat evenly.
Transfer the mixture to a 9x13 inch baking dish.
Sprinkle shredded mozzarella cheese evenly over the top.
Bake for 20 to 25 minutes until the cheese is melted and bubbling.
Let rest for 5 minutes before serving to allow the sauce to set.