An "Affirmation Requesting Nunc Pro Tunc Filing of …" is a sworn statement you file with the court asking the judge to accept a document that was filed late and treat it as if it had been filed on an earlier proper date, usually because you missed the deadline for a good reason (like a clerical error or delay) and want the court to correct the record so the case isn't prejudiced by the timing. ("Nunc pro tunc" literally means "now for then," reflecting the retroactive effect.)