Is this normal for teachers to only call my son his full name?

when we signed my son up for kindergarten we put his full first name because we thought we supposed to put his legal name. We’re Mexican and it’s very long and on the back to school night we told his teacher the nickname he goes by but found out that the teachers are only calling him by his full first name. my son told me they’re doing this for another girl in his class too, only by their full name when she goes by a nickname. Is this normal? Should I have put his nickname instead of full name? it’s not a big deal so I’m not going to say anything I’m just wondering if this is a normal thing

Edit- @unicornsdoexist lmao what? I’m not offended they use his full name, my son doesn’t care and as I said it’s not a big deal. I love his full name I think it’s beautiful and it’s a family name, but like I said it is very long, and he knows his full name, first middle and last. He just goes by the shorter version. That’s normal. It’s like Katherine’s going by Kate or Katie and Alexanders going by Alex etc. we called him by the shorter name when we met the teacher and she asked if that’s what he goes by and we said yes, but still call him his full name. I was just wondering if it was a rule or something