Add the ground chicken and diced tomato, egg, rice, and parsley in a large mixing bowl.
Season with salt and pepper, and mix to combine all ingredients.
Take about 1/4 cup of the chicken mixture and make the meatballs placing them on a plate as you shape them—place in the fridge for 10 minutes.
Add tomatoes, onion, and garlic in a blender. Add 1 cup of chicken stock and blend until smooth.
Heat the olive oil in a soup pot. Add the tomato sauce and cook for 1 minute. Pour the remaining chicken stock and bring to a boil.
Reduce the heat to a simmer and carefully add the chicken meatballs into the simmering broth using a spoon.
Raise the heat to bring the soup to a gentle boil and cook for 30 minutes.
Add carrots, zucchini, and celery. Bring to a boil and keep cooking until vegetables are tender.
Adjust salt to taste, turn off the heat and add the oregano rubbing it between your hands to release its aroma.
Ladle the soup and meatballs into serving bowls and serve with a squeeze of lime.
Notes
When adding the meatballs to the broth, make sure to use a spoon and take the meatballs one by one and carefully add them to the soup so they won't fall apart.
Make this chicken meatballs in soup recipe in advance and store it in the refrigerator for up to three days to enjoy during busy weeknights.
Add different veggies and swap the broth depending on what you have on hand or what you’re in the mood for.