Bring a large pot of salted water to a vigorous boil. Cook pasta according to package instructions until al dente, reserving 1/2 cup of pasta water before draining.

Heat skillet over medium heat, add olive oil and butter. Season chicken with salt, pepper, and garlic powder, cooking for 6-7 minutes per side until golden.

In the same skillet, reduce heat to low and whisk in flour. Gradually add chicken broth and heavy cream until combined, then stir in pesto, lemon juice, and sun-dried tomatoes. Simmer for 3-5 minutes.

Add spinach to the sauce and cook for 2-3 minutes until wilted.

Fold in drained pasta and reserved pasta water as needed for sauce consistency.

Add chicken back into the skillet, combining until heated through. Serve with Parmesan cheese if desired.