Place a large pot on the stove and pour in the chicken stock. Bring it to a gentle simmer over medium heat, with small bubbles just starting to form.
Add the boneless chicken thighs into the simmering broth. Cook for about 10 minutes, until the chicken turns opaque and is cooked through, filling the kitchen with a savory aroma.
While the chicken cooks, chop the carrots and celery into uniform pieces and slice the onion thinly.
Remove the chicken from the pot and set it aside to cool slightly. Add the chopped vegetables and sliced onion into the broth. Let them cook for 5 to 7 minutes, until they soften but still retain some crunch.
While vegetables cook, shred the cooked chicken into bite-sized pieces using two forks.
Return the shredded chicken to the pot and stir well. Season with salt, pepper, and a splash of fresh lemon juice to brighten the flavors.
Let the soup simmer for another 5 minutes, allowing the flavors to meld and the broth to develop a vibrant, savory aroma.
Taste the broth and adjust the seasoning, adding more lemon juice or herbs if desired.
Chop fresh herbs and sprinkle generously over the soup just before serving for a burst of fresh aroma and flavor.
Serve the hot, vibrant chicken soup in bowls, enjoying the tender chicken, crisp vegetables, and bright, flavorful broth.
