Scraping columns from SEDE results
I'd test if not result_sets_col in script.text and continue in that case, to remove a level of nesting:

for script in soup.findAll('script'):
    result_sets_col = 'resultSets'
    if not result_sets_col in script.text:
        continue

    start = script.text.rindex('{', 0, script.text.index(result_sets_col))