Cost of a Furutech IEC and a Dremmel tool you may not own, I’d just buy a decent used PC, take off the female end and drill out a larger hole and buy a new, larger strain relief from Michael Percy. Page 21 - Cord Strain Relief: Collet Type. That’s what I would do. Pull the new cable in as far as you can and solder back to power supply.
https://www.percyaudio.com/Catalog.pdf
Haven’t looked up your Nak but my guess it’s only a two prong plug. I agree add a shielded cable so look up digital two conductor power cable on VH Audio site and buy a Hubbell Hospital Grade male plug and tie the shield to the ground at the wall receptacle. Easy project. I use the VH Audio digital cable and it’s very good. Be surprised you’ll find better for the money. Shielded twisted pair.
https://www.vhaudio.com/wire.html
https://www.vhaudio.com/images/shieldedtwistedpairbulk.jpg
The VH Audio cable mentioned will likely work in the existing strain relief if you’re careful taking it out.