Gather all your ingredients, and bring a large heavy-bottomed pot to a medium heat.
Add a splash of oil to the pot, then sauté the diced onion and minced garlic until fragrant and translucent, about 3-4 minutes. The onions should be soft and slightly shimmering.
Stir in the diced carrots and celery, cooking until they soften slightly and release a sweet aroma, about 5 minutes. The vegetables should be crisp-tender and fragrant.
Add the shredded cooked chicken and rice to the pot, stirring to combine everything evenly.
Pour in the chicken broth, bringing the mixture to a gentle simmer. You should see small bubbles forming around the edges.
Reduce the heat to low and let the soup simmer gently for about 20 minutes. Stir occasionally, watching the rice become tender and the flavors meld together.
Taste the soup and add salt and pepper as needed. For extra brightness, stir in a splash of lemon juice or hot sauce.
Remove the pot from heat and let the soup rest for 5 minutes, allowing the flavors to deepen and the broth to slightly thicken.
Stir in chopped fresh herbs for a burst of herbal freshness and vibrant color.
Serve the soup hot, with a spoonful of herbs on top and a warm piece of bread if desired.