Boil the pasta: Bring a large pot of salted water to a boil. Cook pasta until just al dente according to package directions. Reserve about 1 cup of pasta water, then drain.
Prep the chicken: While the pasta cooks, pull the rotisserie chicken into bite-size pieces.
Aim for 2 cups of meat for solid protein.
Warm the base: In a large skillet over medium heat, add a splash of olive oil. If using, sauté the garlic for 30 seconds until fragrant. Add the cherry tomatoes and cook 2–3 minutes until they soften slightly.
Build the sauce: Lower the heat.
Stir in the pesto along with 1/2 cup chicken broth or pasta water. The goal is a loose, glossy sauce that will coat the pasta.
Add the chicken: Stir in the shredded chicken and warm through for 1–2 minutes. Season with a pinch of salt, black pepper, and red pepper flakes if you like heat.
Toss the pasta: Add the drained pasta and toss until everything is coated.
If it looks dry, add more pasta water a splash at a time until it’s silky.
Greens and finish: Fold in the spinach or arugula until just wilted. Stir in Parmesan, lemon zest, and a squeeze of lemon juice. Taste and adjust seasoning.
Serve: Top with extra Parmesan and a sprinkle of toasted nuts for crunch.
Serve warm.