Boil the pasta. Bring a large pot of salted water to a boil. Cook the pasta until just shy of al dente, according to package directions. In the last 2 minutes, add the broccoli florets to the pot. Reserve 1/2 cup of pasta water, then drain.

Season the chicken. Pat the chicken dry and toss with 1 teaspoon salt, 1/2 teaspoon black pepper, onion powder, and Italian seasoning. This helps it brown and builds flavor right away.

Sear the chicken. Heat 1 tablespoon olive oil in a large skillet over medium-high. Add the chicken in a single layer. Cook 5–7 minutes, stirring once or twice, until browned and just cooked through. Transfer to a plate and tent loosely with foil.

Build the sauce base. Reduce heat to medium. Add the remaining 1 tablespoon olive oil to the skillet. Stir in the garlic and a pinch of red pepper flakes. Cook 30–45 seconds until fragrant—don’t let it brown.

Deglaze. Pour in the chicken broth and scrape up any browned bits. Let it simmer for 2–3 minutes to reduce slightly. Add the lemon zest and a squeeze of lemon juice for brightness.

Make it creamy. Reduce the heat to low. Whisk in the Greek yogurt and Parmesan until smooth. If it looks too thick, splash in some reserved pasta water to loosen. Taste and adjust salt and pepper.

Combine. Add the chicken, drained pasta, and broccoli to the skillet. Toss over low heat for 1–2 minutes so the sauce coats everything. Add more pasta water as needed for a silky finish.

Finish and serve. Top with more Parmesan, a bit more lemon juice if you like, and chopped parsley. Serve hot.