Cook pasta in salted water until al dente. Reserve ½ cup pasta water, then drain.
Season chicken with paprika, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat. Cook chicken until golden and cooked through. Remove and slice.
Lower heat and add butter to the skillet. Once melted, add garlic, Italian seasoning, and chili flakes. Cook until fragrant.
Stir in lemon juice and parsley.
Add pasta and sliced chicken back to the skillet. Toss to coat, adding pasta water as needed for a silky sauce.
Taste, adjust seasoning, and serve hot.