In a large skillet, heat the olive oil over medium-high heat. Add the chicken pieces and season with garlic powder, onion powder, salt, and pepper. Cook for about 5-7 minutes, stirring occasionally, until the chicken is browned and cooked through.
Add the broccoli florets to the skillet and pour in the chicken broth. Bring to a simmer, cover, and cook for about 5 minutes, or until the broccoli is tender.
Stir in the cooked rice, soy sauce, lemon juice, and red pepper flakes (if using). Mix well and cook for an additional 2-3 minutes until everything is heated through.
If desired, sprinkle with grated Parmesan cheese before serving.