Bring a large pot of salted water to a boil and cook the pasta until al dente according to package instructions; drain and set aside.
Season both sides of the chicken breasts with garlic powder, Italian seasoning, paprika, salt, and black pepper.
Heat the olive oil in a large skillet over medium-high heat. Cook the chicken about 5 minutes per side, or until cooked through and no longer pink inside; remove from the pan and set aside to rest.
Reduce heat to medium, add the butter to the same skillet, then add the minced garlic and cook 1 minute until fragrant.
Add the diced tomatoes and (if using) chopped spinach; cook 2–3 minutes until the tomatoes are softened and the spinach is wilted.
Lower the heat and stir in the heavy cream and Parmesan until the cheese melts and the sauce is smooth and creamy; season with salt and pepper to taste.
Slice or cube the cooked chicken, return it to the skillet along with the drained pasta, and toss to coat everything in the sauce; heat through and serve.