Pat the chicken dry, slice into strips or cubes, and season with salt, pepper, and paprika.
Cook chicken in olive oil over medium-high heat until golden and cooked through, then set aside. Meanwhile, cook pasta until al dente, reserving 1 cup of pasta water before draining.
In the same skillet, melt butter, sauté garlic and onion until fragrant, then add cream and simmer gently. Gradually whisk in Parmesan and mozzarella until smooth.
Add cooked pasta and chicken to the sauce, tossing to coat. Gradually add reserved pasta water until sauce reaches desired consistency. Stir in parsley, then season to taste.
Notes
For extra flavor, sprinkle additional parsley or Parmesan before serving.