Heat olive oil and butter in a large deep skillet over medium-high heat.
Season chicken with ½ teaspoon salt, black pepper, Italian seasoning, garlic powder, and paprika.
Add chicken to the skillet and cook for 4–5 minutes, until lightly golden and mostly cooked through. Remove and set aside.
Add onion to the same skillet and cook for 2–3 minutes until softened.
Stir in garlic and cook for 30 seconds.
Add dry orzo and toast for 1–2 minutes, stirring often.
Pour in chicken broth and scrape the bottom of the skillet.
Bring to a simmer, then reduce heat to medium-low. Cook for 8–10 minutes, stirring often, until the orzo is almost tender.
Return chicken to the skillet and cook for 3–4 minutes more, until chicken is fully cooked and orzo is tender.
Stir in heavy cream, parmesan, lemon juice, and spinach if using.
Cook for 1–2 minutes until creamy and the spinach wilts.
Taste and adjust salt if needed. Garnish with parsley and serve warm.