Start by bringing a large pot of salted water to a boil. Cook your pasta according to the package instructions until al dente. Drain and set aside, reserving about ½ cup of pasta water in case you need to loosen the sauce later.
While the pasta boils, heat olive oil in a large skillet over medium-high heat. Season the chicken strips with salt, pepper, and Italian seasoning, then add to the skillet. Sear for about 4–5 minutes per side until golden brown and cooked through. Remove and set aside.
In the same skillet, add a bit more olive oil if needed and toss in the minced garlic and red pepper flakes. Cook for 30 seconds until fragrant. Add the sun-dried tomatoes and cook for another 1–2 minutes, stirring frequently to release their flavor.
Reduce heat to medium-low and pour in the chicken broth and heavy cream. Stir to combine and bring to a gentle simmer. Gradually whisk in the grated Parmesan until fully melted and the sauce is smooth and thickened—about 3–4 minutes.
Fold the chopped spinach into the sauce and stir until wilted. Return the cooked chicken to the skillet and toss to coat with the sauce. Let everything simmer together for 2–3 more minutes so the flavors meld.
Add the cooked pasta to the sauce and toss until fully coated. If the sauce feels too thick, add a splash of reserved pasta water. Taste and adjust salt and pepper as needed. Garnish with fresh basil or parsley before serving.