Cook the Chicken: Heat 2 tablespoons of olive oil in a large skillet over medium heat. Add chicken pieces and cook until browned and cooked through, about 3 minutes per side. Remove and set aside.
Cook the Pasta: Boil water in a large pot and cook the fettuccine according to package instructions. Drain and set aside.
Prepare the Sauce: In the same skillet, add the remaining tablespoon of olive oil over low heat. Add garlic and herbs, cooking for about 1 minute. Increase heat to medium-low, add chicken broth and heavy cream, and simmer for 8 minutes.
Combine and Finish: Reduce heat to low and gradually stir in Parmesan cheese until melted. Add spinach and cook until wilted. Stir in sun-dried tomatoes, cooked chicken, and pasta. Toss everything together until warmed through.
Serve: Serve immediately for best results.
