Step 1: Pat chicken pieces dry and season generously with garlic powder, onion powder, salt, and pepper.
Step 2: Heat olive oil in a large, deep skillet or Dutch oven over medium-high heat. Add seasoned chicken and sear for 5-7 minutes, stirring occasionally, until golden brown and cooked through. Remove chicken from skillet and set aside.
Step 3: Add rinsed long-grain white rice to the same skillet. Stir for 1-2 minutes to lightly toast the rice and scrape up any browned bits from the bottom of the pan.
Step 4: Pour in chicken broth and stir once. Bring to a boil, then reduce heat to low, cover tightly, and simmer for 15 minutes, or until most of the liquid is absorbed by the rice.
Step 5: Stir in the frozen mixed vegetables and dried thyme. Return the cooked chicken pieces to the skillet, nestling them into the rice and vegetables. Cover again and cook for another 5-7 minutes, until the vegetables are tender and the chicken is thoroughly heated through.
Step 6: Remove the lid and stir in the heavy cream. Let the mixture simmer gently, uncovered, for 2-3 minutes, allowing the sauce to thicken slightly. Taste and adjust seasoning as needed.
Step 7: Serve hot, garnished with fresh chopped parsley.