Cook the pasta: Bring a large pot of salted water to a boil. Cook chickpea pasta until just al dente per package directions. Do not overcook—it softens as it sits in the dressing.
Drain and rinse quickly under cool water to stop cooking.
Pat the pasta dry: Shake off excess water and spread the pasta on a sheet pan for 5 minutes. A drier surface helps the creamy pesto cling better.
Make the creamy pesto dressing: In a large bowl, whisk pesto, Greek yogurt, olive oil, lemon zest, 1–2 teaspoons lemon juice, grated garlic, a pinch of salt, and black pepper. Adjust acidity and salt to taste.
You want it thick but spoonable.
Toss the base: Add cooled pasta and chicken to the bowl. Fold until everything is coated in the dressing.
Add veggies and herbs: Gently mix in tomatoes, cucumber, spinach, fresh basil, and red onion if using. Sprinkle in red pepper flakes for a touch of heat.
Finish with cheese and crunch: Fold in Parmesan.
Top with toasted pine nuts or almonds for texture. Taste and adjust salt, pepper, or lemon.
Chill briefly: Let the salad rest in the fridge for 20–30 minutes so flavors meld and the dressing thickens slightly.
Serve: Give it a quick toss. If it seems tight after chilling, loosen with a teaspoon or two of water or olive oil.
Serve cool or at room temperature.