Depending on your domain registrar, you can use different nameservers with the same IPs. i.e even if someone checks the whois of your domain, they will see its own nameservers.
like suppose you have just three IPs in total, it can be used to host 3 domain names with its own dedicated IP, but still having separate nameservers.
domain1.com using ns1.domain1.com & ns2.domain1.com
domain2.com using ns1.domain2.com & ns2.domain2.com
domain3.com using ns1.domain3.com & ns2.domain3.com
domain1.com will have dedicated IP of 1.1.1.1
domain2.com will have dedicated IP of 2.2.2.2
domain3.com will have dedicated IP of 3.3.3.3
You will register the nameservers with these IPs
ns1.domain1.com & ns2.domain1.com with 2.2.2.2 & 3.3.3.3
ns1.domain2.com & ns2.domain2.com with 2.2.2.2 & 3.3.3.3
ns1.domain3.com & ns2.domain3.com with 2.2.2.2 & 3.3.3.3
Out of quite a few domain registrars I have dealt with, around 2 of them don't support mutiple nameserver registration with same IP. So it will all depend on where you registered the domain with.