01 - Heat olive oil in a large pot or deep skillet over medium-high heat. Season the diced chicken with salt and pepper, then cook until golden and cooked through, about 5-6 minutes. Transfer to a plate and set aside.
02 - Melt the butter in the same pot. Add the onion, carrots, and celery, sautéing until the vegetables are softened, about 5 minutes.
03 - Sprinkle the flour over the softened vegetables, stirring continuously, and cook for 1 minute to form a roux.
04 - Gradually pour in the chicken broth while stirring constantly to avoid lumps, then bring the mixture to a gentle simmer.
05 - Stir in the orzo pasta, garlic powder, thyme, and parsley. Reduce the heat to medium-low and cook uncovered, stirring occasionally, until the orzo is al dente, about 10 minutes.
06 - Fold the cooked chicken and frozen peas into the pot, simmering for an additional 3 minutes.
07 - Pour in the heavy cream and Parmesan cheese, stirring until the sauce is rich and creamy. Adjust the salt and pepper to taste before serving hot.