Bring a pot of salted water to a boil. Add the orzo and let it cook according to package directions. Drain and set aside (reserve 3/4 cup of water from the pasta).

In a large skillet, heat the olive oil, then add the chicken chunks and sprinkle liberally with salt and pepper. Cook until browned, then flip and cook on the other side. Add the mushrooms (the chicken doesn't need to be cooked all the way through) and cook for about 5 minutes.

Add the basil, garlic, and tomatoes. Cook about 3 minutes, until the tomatoes are not juicy anymore. Add the cream cheese and stir to coat the vegetables.

Stir in the reserved pasta water, stir and bring to a simmer. Cook for about 2 minutes until thickened, then stir in orzo, lemon juice and Parmesan cheese. Salt and pepper to taste, top with fresh basil (if desired), and serve hot.