user: Question: When ΚΑΘ are the letters what is the nickname?
Columns: ['Letters', 'Organization', 'Nickname', 'Founding Date', 'Founding University', 'Type', 'Canadian Chapters']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['ΑΓΔ', 'Alpha Gamma Delta', '"A G D" or "Alpha Gam" or "Gams"', '1904-05-30', 'Syracuse University', 'Social', '8 Active, 2 Inactive']
SQL:

assistant: SELECT "Nickname" FROM "Table" WHERE "Letters" = 'ΚΑΘ';