Fry chopped onions, carrots, celery and garlic in olive oil. Turn on low heat and stir. After 5 minutes, put chicken in a saucepan and pour in the broth. If the broth does not cover the fillets, add more broth or water. Boil for 20 minutes or until meat is cooked thru.
Take meat out of the broth and tear it with two forks. Put the chicken back into the broth. With wet hands, form the mixed matzo dough into balls 1.5" or so in size. Put into the broth and cook for another 5-7 minutes.
During this time they will increase slightly in size and soak up the liquid. Soup can be served now.