Heat the olive oil in a large skillet over medium heat. Add the chicken and season with salt and pepper. Cook for 4 to 5 minutes on each side until cooked through. Transfer to a plate and set aside.

Without wiping the skillet, add the onion and mushrooms. Season with salt and pepper. Cook for about 5 minutes until the onion is soft and the mushrooms are cooked. Stir in the garlic and mix. Add the orzo to the skillet and cook for a couple minutes until toasted. Pour in the lemon juice and scape off any bits stuck to the pan. Add the chicken stock to the skillet. Add the thyme and oregano. Bring the broth to a boil and then reduce to low heat. Simmer, stirring frequently, for 10 minutes or until the orzo is tender.

Stir in the chopped parsley and spinach, lemon zest, and the cooked chicken. Cook for a minute until the spinach wilts. Add the whole milk and parmesan cheese to the skillet and stir well. Once the cheese has melted, you can serve in bowls!