NBC has cut ties with Scot Chastain, a 23-year company veteran who had led affiliate marketing and planned many of the network’s spring upfront presentations to ad buyers. A company rep’s only comment to Deadline was the following statement: "A thorough internal review was conducted. Scot Chastain is no longer with the company." It remains unclear what conduct Chastain is accused of, or the nature of the review or the alleged misconduct. Chastain’s most recent title was…