Peel and slice your onion in tiny pieces and make it sweat on medium heat in the olive oil in a Dutch oven.
In the meantime, peel and slice the carrots and sweet potato. Transfer them to the Dutch oven along with the parsley, tarragon and pinch of salt. Add the chicken legs and pour the water on the whole thing. Cover the Dutch oven.
Let it cook for about 45 minutes or until carrots and sweet potato are tender and the chicken is cooked. Then turn off the heat. Remove the chicken legs from the Dutch oven and put them on a plate.
Optional step: using an immersion blender, briefly mix (for 2 seconds) your vegetables in order to thicken your broth and give it more flavor.
Prepare the noodles according to instructions written on the package (they might change slightly from one brand to another and depending on the type of noodles you are using). I usually just add the noodles to the soup which is still extremely hot, so they cook directly in the soup in 5 minutes, even though my French oven is out of the stove. In the meantime, shred the chicken legs, then add the shredded chicken back to the soup. And voilà.Bon appétit !
Please keep in mind that the nutritional information is calculated using a nutrition facts calculator. It is a rough estimate and can vary greatly based on products used.