Reference another table within base to display country code

Hey there folks!

Likely a very silly question, but I have been spinning my wheels in this a touch and thought to ask the experts to assist on this one.

I have a form to capture the addresses of people with the countries as a dropdown. To send this info into my shipping companies database with Zapier I need countries listed as specified abbreviations.

Without building the world’s largest IF statement, how can I build a sudo lookup field for this single dropdown field to roll up/link the other table and display in the addresses table so I can pull this into Zapier.

Thanks for your help,