Prep the ingredients: Slice the onion, bell pepper, zucchini, and squash into thin strips or half-moons. Halve the cherry tomatoes. Cut broccoli into small florets. Mince the garlic. Pat the chicken dry and season with salt, pepper, and a pinch of Italian seasoning.

Boil the pasta: Bring a large pot of salted water to a rolling boil. Cook pasta until just al dente. Reserve 1 cup of pasta water before draining. Set pasta aside.

Sear the chicken: Heat 1 tablespoon olive oil in a large skillet over medium-high. Add chicken in a single layer. Cook 4–6 minutes until golden and cooked through, stirring once or twice. Transfer to a plate.

Sauté the aromatics: In the same skillet, add 1 tablespoon olive oil. Add onion and a pinch of salt. Cook 2 minutes until slightly softened. Stir in garlic and red pepper flakes (if using) for 30 seconds, just until fragrant.

Cook the veggies: Add bell pepper, zucchini, squash, and broccoli. Season with salt and pepper. Cook 4–6 minutes, stirring occasionally, until crisp-tender. If the pan looks dry, add a splash of broth or pasta water.

Add tomatoes and greens: Stir in cherry tomatoes and spinach (or kale). Cook 1–2 minutes until tomatoes start to soften and greens wilt.

Build the sauce: Reduce heat to medium. Add lemon zest, lemon juice, and chicken broth (about 1/2 cup). Simmer 1–2 minutes to meld flavors and slightly reduce.

Combine with pasta and chicken: Return the chicken to the skillet. Add the cooked pasta. Toss to coat, adding reserved pasta water as needed to create a light, silky sauce that clings to the pasta.

Add cheese and herbs: Off the heat, stir in grated Parmesan and a handful of chopped parsley or basil. Taste and adjust salt, pepper, or lemon.

Serve: Finish with a drizzle of olive oil and extra Parmesan if you like. Serve warm.