Domains do not have an IP address of their own. The domain has subsequent records, A Records, which can contain an IP address so that the site directs traffic to the specified server. However, the A Records are all managed by the servers specified by the NS Records.
In effect, the NS Records specify who is managing the domain name itself.
The A Records, and all other records, are managed by that subsequent entity, separately (in some cases) from the NS Records themselves at the original registration provider.
The nameservers themselves do point to an IP, of course, but the action of pulling that IP is performed automatically by any software that reads the nameserver, which is the entire purpose of having a nameserver that can point dynamically at the IP address, instead of having to manually use the IP addresses themselves, as the IP's can over time change, etc.
At the end of the day, the only information applicable is the Nameservers themselves, insofar as setting up a domain name with an external provider goes. Any other records/IP's are handled separately from the NS Records.