Cube 1 pound boneless skinless chicken breasts into 1-inch pieces. Slice 8 ounces white or cremini mushrooms and set them aside.
Heat 2 tablespoons olive oil in a large, deep skillet (12-inch or larger) over medium-high heat. Add in cubed chicken and season with 1 teaspoon salt, 1 teaspoon garlic powder and 1/2 teaspoon black pepper. Cook for 6–8 minutes, stirring occasionally, until the chicken starts to brown.
Add the sliced mushrooms to the skillet and cook for about 5 minutes, stirring occasionally, until the mushrooms are softened.
Add 4 cups reduced sodium chicken broth, 2 tablespoon Italian seasoning, and 16 ounces orzo. Turn the heat to high and bring to a boil.
Once boiling, reduce the heat to medium, cover the skillet with a lid, and cook the orzo until it is al dente. Stir occasionally to prevent the orzo from sticking to the bottom of the pan. Cooking time will vary depending on the brand of orzo; refer to package instructions (typically about 9–10 minutes).
Once the orzo is cooked, reduce the heat to a simmer. Add 1 cup heavy cream, 1 cup baby spinach, and 1/4 cup finely chopped sun-dried tomatoes. Stir to combine and cook for 1 minute, or until the spinach wilts.
Remove the skillet from the heat and sprinkle 1 cup shredded parmesan cheese over the top. Stir until the cheese melts and is fully incorporated. Serve hot.