Pat the chicken dry, slice into strips or cubes, and season with salt, pepper, and paprika.
Cook chicken in olive oil until golden and cooked through, then set aside. Boil pasta until al dente, reserving 1 cup of pasta water, then drain.
In the same skillet, melt butter, sauté garlic and onion until fragrant, then add cream and simmer gently. Gradually stir 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, taste, and adjust seasoning. Garnish with more parsley before serving.
Notes
For a richer flavor, use freshly grated cheese and high-quality cream.