Cook the pasta in a large pot of salted boiling water until al dente, following package instructions for about 8-10 minutes. Reserve a cup of pasta water before draining.

Heat a large skillet over medium-high heat and add olive oil and butter. Season chicken with garlic powder, salt, and pepper, then sear for 5-6 minutes per side until cooked through. Remove from heat and let rest before slicing.

In the same skillet, add flour and stir for 1-2 minutes. Gradually pour in chicken broth while stirring to create a smooth mixture.

Lower heat and stir in heavy cream, pesto, and lemon juice. Simmer for 3-4 minutes until thickened.

Add sun-dried tomatoes and spinach, stirring until spinach wilts, about 2-3 minutes.

Add the drained pasta to the skillet and toss to coat with sauce, adding reserved pasta water if needed for desired consistency.

Slice the chicken and serve on top of pasta, optionally sprinkle with Parmesan cheese.