Bring a large pot of salted water to a boil. Cook pasta until al dente according to package instructions. Reserve ½ cup pasta water, then drain and set aside.
Season sliced chicken with salt, pepper, and Italian seasoning. Heat olive oil in a skillet over medium heat. Cook chicken until golden and fully cooked (5 to 7 minutes). Remove and set aside.
In the same skillet, melt butter. Add minced garlic and sauté for 1 minute until fragrant. Pour in heavy cream and let it gently simmer for 2 to 3 minutes.
Stir in sun-dried tomatoes and fresh spinach. Cook until spinach wilts and blends into the sauce.
Add cooked pasta and chicken back into the skillet. Toss everything together. Stir in parmesan cheese and mix until the sauce becomes creamy.
If the sauce is too thick, add a splash of reserved pasta water until you reach a silky consistency.
