Bring a large pot of well-salted water to a boil. Cook pasta according to package directions until just al dente, about 8 to 10 minutes for fettuccine. Reserve 1/4 cup of pasta water before draining. Drain and set pasta aside.

Pat chicken breasts dry with a paper towel. Season generously with salt and pepper on both sides.

Heat olive oil in a large heavy-bottomed skillet over medium-high heat until shimmering. Add chicken and cook undisturbed for 5 to 7 minutes per side until deep golden brown and the internal temperature reaches 165 degrees F. Transfer to a cutting board and rest for 5 minutes.

Reduce heat to medium. Add minced garlic to the same skillet and stir constantly for about 1 minute until fragrant. Do not let it burn.

Add chopped sun-dried tomatoes and stir for 1 more minute.

Pour in heavy cream and chicken broth. Stir to combine and bring to a gentle simmer over medium heat. Do not boil.

Slowly whisk in freshly grated Parmesan a little at a time until the sauce is smooth and slightly thickened, about 2 to 3 minutes. Add a splash of reserved pasta water if the sauce gets too thick.

Slice the rested chicken and return it to the skillet with the cooked pasta and fresh spinach. Toss until spinach wilts and pasta is coated. Add Italian seasoning, taste and adjust salt and pepper. Cook 2 more minutes and serve immediately.