Heat olive oil and butter in a large skillet over medium heat. Add chicken, season lightly with salt and pepper, and cook for 4–5 minutes until lightly golden and cooked through. Remove chicken from skillet and set aside.
In the same skillet, add minced garlic and cook for 30 seconds until fragrant.
Stir in the uncooked orzo, then pour in the chicken broth. Bring to a gentle simmer.
Reduce heat to medium-low and cook, stirring occasionally, for 8–10 minutes, until the orzo is tender and most of the liquid is absorbed.
Stir in the heavy cream, lemon zest, lemon juice, red pepper flakes (if using), and Parmesan cheese.
Return the cooked chicken to the skillet and stir to combine. Simmer gently for 2–3 minutes until the sauce is creamy and the chicken is heated through.
Taste and adjust seasoning. Remove from heat and garnish with fresh herbs before serving.