Prep the chicken and broccoli. Pat the chicken dry and season with 1 teaspoon salt, 1/2 teaspoon pepper, Italian seasoning, onion powder, and smoked paprika.
Cut the broccoli into small, even florets so they cook quickly.
Heat the skillet. Add 1 tablespoon olive oil to a large skillet over medium-high heat. When the oil shimmers, add half the chicken in a single layer. Cook 3–4 minutes per side until browned and cooked through.
Transfer to a plate and repeat with remaining chicken, adding more oil if needed.
Sauté the broccoli. Reduce heat to medium. Add 1 tablespoon olive oil and the broccoli. Season with a pinch of salt and pepper.
Cook 3–4 minutes, stirring occasionally, until the edges brighten and pick up some color.
Steam to tender. Pour in 1/4 cup chicken broth, cover, and steam 2–3 minutes until crisp-tender. Uncover and let any excess liquid evaporate.
Build the garlic base. Push broccoli to the edges. Add butter to the center.
When melted, add minced garlic and red pepper flakes. Stir 30 seconds until fragrant—don’t let it brown.
Make the sauce. Pour in the remaining 1/4 cup broth and bring to a gentle simmer. Return the chicken and any juices to the pan.
Toss everything to coat.
Add Parmesan and lemon. Turn off the heat. Sprinkle in the Parmesan and squeeze in lemon juice. Toss until the sauce turns glossy and clings to the chicken and broccoli.
Taste and adjust salt, pepper, or lemon as needed.
Finish and serve. Top with chopped parsley and a little extra Parmesan. Serve hot on its own, over rice, or with buttered noodles.