Nested columns

On my website acl-tx.com I want to use two columns (2/3 and 1/3) nexted in full width column.

I used this structure (used generic code to spare you the full code) but it doesn’t work:
[su_row][su_column size=”1/1″]
[su_row]
[su_column size=”2/3″]2/3 Column content[/su_column]
[su_column size=”1/3″]1/3 Column content[/su_column]
[/su_row]
[/su_column][/su_row]

Can you direct me what is the correct structure to do so.

https://wordpress.org/plugins/shortcodes-ultimate/