In a large heavy bottomed pot or dutch oven, heat a couple of drizzles of olive oil over medium high heat.
Add chicken pieces. Cook just until lightly browned, the chicken doesn't have to be cooked through. Season with ½ teaspoon garlic salt. Remove to a platter using a slotted spoon.
To the pot add more oil, if needed. Add onion. Cook for 2-3 minutes over medium-high, just until beginning to brown. Add garlic, cook for one minute longer.
To the pot add chicken, pasta, crushed tomatoes, tomato paste, stock, 1 teaspoon garlic salt, pepper and ⅓ cup Parmesan cheese. Mix well. Bring to a boil, then lower to medium-low (strong simmer) and simmer covered for 15-20 minutes or just until pasta is al dente.
Uncover, add ½ cup shredded mozzarella plus chive and onion cream cheese. Stir until cream cheese is completely melted and mozzarella is fully combined.
Sprinkle top with remaining mozzarella and Parmesan, turn off the heat. Let stand uncovered until melted.
Serve immediately garnished with fresh parsley.
At the end of cooking, you can thin further using additional chicken stock. Likewise, you can thicken using additional tomato paste.