https://www.godaddy.com/help/add-my-own-host-names-as-nameservers-12320
Just for branding purposes, assuming that the portfolio is already hosted:
Step1: determine the ip addresses of the dns servers (if your-forsale-domain.com is currently using dns1.somehosting.com and dns2.somehosting.com, then you may assign ip address of dns1.somehosting.com to dns1.names-for-sale.com and use the similar scheme for dns2).
Step2: add those records to a dns zone serving names-for-sale.com
Step3: perform nameserver registration using control panel of the registrar you registered names-for-sale.com with. Example: above godaddy help link
After Step3 is finished, you would be able to assign dns1.names-for-sale.com and dns2.names-for-sale.com to other domains as their dns ( such as to your-forsale-domain.com from step1).
SIde effect: Should your hosting company (or parking company, or marketplace) decide to change IPs of their dns servers - then you will need to perform the same change. The problem is that they would not necessary tell you about the change, unless they officially support and recommend using branded dns servers... Webhosting reseller systems usually do this, but domain parking companies and/or marketplaces normally don't.
Alternative: run your own dns servers, a couple of VPS would be OK. So you will not experience any unexpected IP change side effects...