Heat olive oil in a large skillet over medium-high heat until shimmering.
Season the chicken pieces with kosher salt, black pepper, and garlic powder.
Add the chicken to the skillet and cook, stirring occasionally, until browned and cooked through, about 5-6 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the chopped onion and sauté until softened, about 3-4 minutes.
Add the minced garlic and cook for 30 seconds until fragrant.
Add the orzo pasta to the skillet and stir to coat with the oil and onion mixture.
Pour in the chicken broth and bring to a boil.
Reduce heat to medium-low, cover, and simmer until the orzo is tender and most of the liquid is absorbed, about 10-12 minutes.
Stir in the heavy cream, Parmesan cheese, lemon zest, lemon juice, and butter until the sauce is creamy and well combined.
Return the cooked chicken to the skillet and stir to combine and heat through, about 2 minutes.
Remove from heat and sprinkle with chopped fresh parsley before serving.