Bring a large pot of salted water to a rolling boil. Add short pasta and cook until al dente, about 8-10 minutes. Reserve ½ cup of pasta water, then drain and set aside.

Heat a large skillet over medium-high heat. Add olive oil and butter. Season chicken with garlic powder, salt, and pepper. Sauté chicken for 5-6 minutes on each side until golden and cooked through. Remove from skillet and let rest.

In the same skillet, lower heat and sprinkle in all-purpose flour. Stir for about 1 minute. Gradually add chicken broth, cream, pesto, lemon juice, and sun-dried tomatoes, whisking until smooth.

Allow sauce to simmer for about 5 minutes, stirring occasionally until it thickens slightly.

Add fresh spinach into the skillet. Stir and cook for 2-3 minutes until the spinach wilts.

Add drained pasta to the skillet with sauce and gently toss until coated. Add reserved pasta water to adjust the sauce consistency as needed.

Fold in sliced chicken and mix gently. Heat through if necessary.

Serve hot, garnished with Parmesan cheese if desired.