Whisk ricotta, milk, and Parmesan for 10 to 15 seconds until softly whipped; loosen with more milk if needed.
Heat the reserved tomato oil in a heavy pot. Season chicken with half the salt and pepper, cook for 3 minutes, then remove while still raw inside.
Cook onion and garlic for 3 minutes until translucent. Add tomato paste and sun-dried tomatoes; cook for 1 minute.
Add wine and simmer for 1 to 2 minutes until mostly evaporated.
Add pasta, chicken and its juices, crushed tomatoes, stock, and remaining salt and pepper.
Bring to a boil, then simmer uncovered over medium-high heat for 15 minutes, stirring regularly.
When pasta is al dente and most liquid is absorbed but the dish remains slightly soupy, stir in basil.
Divide into bowls, top with whipped ricotta, and garnish with basil.