01 - Bring a large pot of salted water to a rolling boil. Cook pasta according to package directions until al dente. Reserve approximately ½ cup pasta cooking water, then drain thoroughly.
02 - In a food processor, combine basil, pine nuts, garlic, Parmesan, lemon juice, and a pinch of salt and pepper. Process while slowly drizzling in olive oil until a smooth, emulsified pesto forms. Taste and adjust seasoning as needed.
03 - Heat 1 tablespoon olive oil in a large skillet over medium heat. Add chicken pieces and cook for 6-7 minutes, stirring occasionally, until golden brown and cooked through. Season lightly with salt and pepper. Transfer to a plate and set aside.
04 - Add cherry tomatoes and spinach to the same skillet. Sauté for 2 minutes until just softened but still vibrant.
05 - Reduce heat to low. Return chicken to the skillet and add drained pasta. Stir in pesto mixture, adding splashes of reserved pasta water as needed to create a light, glossy sauce that evenly coats the pasta. Serve immediately, garnished with additional Parmesan and fresh basil.