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.
Pat chicken dry and season both sides with garlic powder, Italian seasoning, paprika, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat. Add the chicken and cook about 5 minutes per side, or until cooked through and no longer pink inside; remove chicken to a plate and keep warm.
Reduce heat to medium, add butter to the same skillet, then sauté the minced garlic about 1 minute until fragrant.
Add diced tomatoes and chopped spinach (if using) and cook 2–3 minutes until tomatoes are softened and spinach is wilted.
Lower the heat, pour in the heavy cream and whisk in the Parmesan until the sauce is smooth and creamy; season with a pinch of salt and pepper to taste.
Slice or cube the cooked chicken and return it to the skillet, then add the drained pasta and toss to combine and coat with the sauce.
Serve immediately, adjusting seasoning if needed.
