user: ### NOW ANSWER:
Question: Which episodes did Nelson McCormick direct?
Columns: ['Series #', 'Season #', 'Title', 'Directed by', 'Written by', 'Original air date']
Types: ['real', 'real', 'text', 'text', 'text', 'text']
Sample row: [180.0, 1.0, '" Chaos Theory "', 'Jonathan Kaplan', 'Jack Orman and R. Scott Gemmill', 'September26,2002']
SQL:

assistant: SELECT "Written by" FROM "Table" WHERE "Directed by" = 'Nelson McCormick';