Start by heating olive oil in a large pot over medium-high heat. Add the onion, carrots, and celery, cooking until they begin to soften and release their aroma. Stir in garlic, thyme, and rosemary, letting them cook just long enough to release their fragrance.
Push the vegetables to the side of the pot and add the chicken pieces. Let them cook until they’re lightly browned on all sides. This step builds extra flavor into the broth.
Pour in the chicken broth and water, scraping the bottom of the pot to release any flavorful bits. Bring the mixture to a boil, then lower the heat and cover. Let it simmer until the chicken is fully cooked and tender.
Toss in the corn and green beans, stirring them into the broth. Let everything cook together until the vegetables are tender but still vibrant in color.
Taste the soup and season with salt and pepper as needed. Finish with a sprinkle of fresh parsley or cilantro for a burst of freshness right before serving.