Bring a large pot of salted water to a boil. Add the pasta and cook until al dente, about 10-12 minutes. Reserve ½ cup of pasta water before draining.

In a large skillet, heat olive oil and butter over medium-high heat. Season chicken with garlic powder, salt, and pepper. Cook for 5-6 minutes on each side until golden brown and 165°F internally. Let rest before slicing.

In the same skillet, reduce heat to medium and add flour, stirring for about 1 minute until lightly golden.

Gradually pour in chicken broth, stirring to avoid lumps. Add heavy cream, pesto, and lemon juice. Stir in sun-dried tomatoes and simmer for 3-4 minutes.

Add spinach to the sauce and stir until wilted, about 1-2 minutes.

Combine the drained pasta with the creamy sauce. Adjust thickness with reserved pasta water if necessary.

Slice the rested chicken and either fold it into the pasta or place it on top. Garnish with Parmesan cheese if desired.