Hola Zachary, the difference in Chico and Chica, Chico means Boy and Chica means Girl. Niño is a little boy and Niña is a little girl. The difference is that niño is considered younger than chico. Niño is used for child or children (less than 10 years old). Chico is used for older than a child, but younger than adult like a minor or teenager. Same goes for chica is used for older than a child, but younger than an adult. Example: El chico come pan= The boy eats bread. El niño come pan= The child(little boy) eats bread. I hope I was able to help you. If you have any more question feel free to contact me me.

Hola Zachary, en España cuando hablamos de un niño/a nos referimos literalmente a la edad de la infancia. Chica/o se suele usar cuando hablamos de gente joven pero más para denotar género y no tanto edad, aunque es verdad que se usa generalmente para gente joven. A veces de forma muy informal en Latinoamérica o España se usa la expresión niña/o para gente joven, cuando hablamos de forma cariñosa. Espero haberte ayudado, un saludo :)

Hola, Zachary. It depends on the country, really. In Chile, niño and niña are for boy and girl respectively, while chico and chica mean small (masculine and feminine). In other countries like Argentina it can mean kids any age or even boyfriend / girlfriend. But, again, it depends on the country, I'm sure it's used differently in other Latin American countries. I hope it was helpful. If you need any more information feel free to contact me :) Nos vemos!