To get the emoji flag of each country, you could join with my public table fh-bigquery.util.country_emoji_flags . For example:

WITH countries AS ( SELECT * FROM UNNEST(['cl','us','in','jp']) country ) SELECT * , (SELECT emoji FROM `fh-bigquery.util.country_emoji_flags` WHERE country=iso_lower) emoji , (SELECT name FROM `fh-bigquery.util.country_emoji_flags` WHERE country=iso_lower) country_name FROM countries

If you want to re-build the table, find the .tsv at: