Place a large pot on the stove and pour in the chicken stock. Bring it to a gentle simmer over medium heat, watching for small bubbles and a fragrant aroma.
Add the boneless chicken thighs to the simmering stock. Cook for about 10 minutes, until the chicken is just cooked through and tender, with a slight bubbling around the edges.
While the chicken cooks, chop the carrots into small, uniform pieces and slice the onion thinly. Prepare the celery by chopping it into small sticks.
Remove the chicken thighs from the broth and set aside to cool slightly. Add the chopped carrots, celery, and sliced onion into the simmering broth. Cook for 5 to 7 minutes until the vegetables are tender but still vibrant and slightly firm.
While the vegetables simmer, shred the cooked chicken into bite-sized pieces using two forks or your hands. Return the shredded chicken to the pot, stirring gently to combine.
Season the soup with salt and pepper to taste. Add a splash of lemon juice to brighten the flavors and stir well.
Let the soup simmer for another 2–3 minutes, allowing the flavors to meld and the aroma to develop into a fresh, savory scent.
Taste the broth and adjust seasoning if needed, adding more lemon juice for brightness or salt and pepper for balance.
Sprinkle freshly chopped parsley or dill over the hot soup for a burst of herbal freshness and aroma.
Serve the vibrant chicken soup hot, with colorful vegetables floating in a clear, flavorful broth, garnished with herbs and a squeeze of lemon.
