Heat the olive oil in a large pot or Dutch oven over medium heat.
Season the chicken pieces with salt and pepper. Add the chicken to the pot and cook until browned on all sides. Remove the chicken from the pot and set it aside.
In the same pot, add the diced onion and minced garlic. Sauté until the onion becomes translucent and the garlic is fragrant.
Add the sliced carrots, celery, and diced potatoes to the pot. Stir and cook for a few minutes until the vegetables start to soften.
Pour in the chicken broth and add the dried thyme and bay leaf. Season with additional salt and pepper to taste.
Return the browned chicken pieces to the pot, along with any juices that may have accumulated. Stir to combine.
Bring the stew to a boil, then reduce the heat to low. Cover the pot and let the stew simmer for about 30-40 minutes, or until the chicken is cooked through and the vegetables are tender.
Remove the chicken pieces from the stew and set them aside to cool slightly. Once cool enough to handle, remove the chicken from the bones (if using bone-in pieces) and shred or chop the meat into bite-sized pieces. Discard the bones and return the chicken to the pot.
Add the frozen mixed vegetables to the pot and stir to combine. Continue simmering the stew for an additional 5-10 minutes, or until the frozen vegetables are heated through.
Taste the stew and adjust the seasoning if needed. Remove the bay leaf.
Serve the chicken stew hot, garnished with chopped fresh parsley if desired.This chicken stew with mixed vegetables is a versatile recipe, and you can customize it by adding other vegetables or herbs based on your preference. Enjoy the comforting flavors and hearty goodness of this delicious dish!