Source in addition to the CMOS 17th edition: "How Do I Format My Class Paper in Chicago Style." CMOS Shop Talk (blog). Chicago Manual of Style, July 18, 2017. http://cmosshoptalk.com/2017/07/18/how-do-i-format-my-paper-in-chicago-style/.
Quotation within Quotation
"When you are quoting from a resource and that quote includes an internal quote, 'use single quotation marks for the internal quote!' and include punctuation for that internal quote within the single quotation marks."