Cook pasta in salted water according to directions listed on package, reserve 1 cup pasta water before draining pasta.
Drain water (reserve 1 cup) and return pasta to pot. Set pot over medium-low heat and add olive oil, lemon zest, lemon juice, ricotta, 1/2 cup hot reserved pasta water and parmesan and toss to evenly coat.
Add in more pasta water as desired to thin and season with salt and pepper to taste, cook and toss, about 2 minutes, until ricotta is heated through. Toss in spinach and grilled chicken. Serve warm topped with more parmesan if desired.
Optional to brush the chicken lightly with olive oil and season both sides salt, pepper and garlic powder before grilling.