If you have RCE, there's a % Complaints and # Complaints measures available that you can add alongside the email name attribute (with filters added so that you see only the intended emails) in the email analysis report.
If you don't have RCE there's a method of approximation that you may employ! You can create a SL with the below config that'll let you know people who reported your email(s) as spam and unsubscribed from it. You'd then need to get a little crafty and view the email activities near the Unsubscribed activity to get a rough idea if they reported the email you're interested in fixing (i.e., if the email was one of the nurture email) or it was from a different email. You certainly cannot know for sure which email they reported and unsubscribed from by this method as unsub activity only shows the reason and not any of the email attributes for you to trace it back to the actual email in the first place. You can however add an additional filter to include only the people who were sent the nurture email to the CDV filter in the SL which'll narrow down the list of people for you to audit.
You can refer this and this post as a reference for improving the overall email deliverability/spam complaints.
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