Toss chicken pieces with black pepper, half the lemon zest, and 1/2 teaspoon salt until evenly coated.

Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 5 minutes, stirring occasionally, until lightly browned. Remove chicken to a plate and set aside.

Add onion to skillet and cook for 3 minutes, stirring frequently, until softened. Incorporate garlic and cook for 30 seconds until fragrant.

Stir orzo into onion mixture and cook for 1 minute, allowing pasta to lightly toast.

Pour in chicken broth and remaining salt. Return chicken to skillet and bring mixture to a boil. Reduce heat to medium-low and cover. Simmer for 8 minutes.

Uncover skillet and stir in broccoli florets. Cover again and cook for 3–4 minutes, until broccoli is crisp-tender and orzo is al dente.

Fold in butter, lemon juice, Parmesan cheese, and remaining lemon zest. Stir until melted and creamy. Taste and adjust salt or pepper as needed.

Transfer skillet contents to serving bowls and garnish with fresh parsley.