Bring a large pot of salted water to a boil and cook pasta according to package instructions until al dente. Reserve ½ cup pasta water, then drain pasta.
Heat olive oil in a large skillet over medium-high heat.
Season chicken with salt, pepper, and Italian seasoning.
Cook chicken for 5–7 minutes until golden brown and fully cooked. Remove and set aside.
In the same skillet, add zucchini and cook for 3–4 minutes until slightly tender.
Add garlic and cook for 1 minute until fragrant.
Reduce heat to medium and add butter, chicken broth, and heavy cream. Stir well.
Slowly add Parmesan cheese while stirring continuously until sauce becomes creamy and smooth.
Return chicken to skillet and add cooked pasta. Toss until fully coated in sauce.
Add reserved pasta water if needed to loosen sauce.
Garnish with parsley, extra Parmesan, or red pepper flakes if desired.
Serve warm immediately.