[ainiriand]

El niño -> the kid.

El chico -> the boy.

[umanwizard]

What’s the difference between “boy” and “[male] kid” ?

[andrewnicolalde]

I’d say “el chico” translates more to “the lad”, but perhaps this is a matter of regional dialects.

[guhidalg]

There absolutely are regional differences with these particular words. People will understand if you use either one but they’ll know you’re not of that place if you use the less common one.