Cook the pasta in salted water according to package directions until al dente. Drain and rinse with cold water to cool the pasta.
1 pound uncooked rotini pasta
While the pasta is cooking, toast the pine nuts. Place them in a dry skillet over medium-low heat and stir frequently for 3–5 minutes, until golden brown. Set aside to cool.
¼ cup pine nuts
In a large mixing bowl, combine the cooled pasta, cubed chicken, halved tomatoes, chopped cucumber, and diced red onion. Stir gently to combine.
3 cups cooked chicken, 1 pint grape tomatoes, 1 cup cucumber, ½ cup red onion
Add the chopped arugula and spinach to the bowl and stir to distribute the greens evenly.
2 cups baby arugula and spinach
Add the jar of pesto and the sun-dried tomatoes. Mix everything until all ingredients are well coated.
6.7 ounce jar basil pesto, ½ cup sun-dried tomatoes
Stir in the shredded Parmesan, mozzarella pearls, and toasted pine nuts until evenly distributed.
⅓ cup shredded Parmesan cheese, 4 ounces mozzarella pearls
Cover the bowl and refrigerate the pasta salad for at least 30 minutes before serving to let the flavors blend.
Before serving, garnish with additional Parmesan and pine nuts, if desired.