The Following steps may help you to get your name servers configured in Plesk

1. Click Domains in the navigational bar on the left.
2. Click on the domain you would like to setup the nameserver under (e.g. nsdomain.com)
3. In the Services section, click DNS.
4. In Add a DNS Record, choose NS for record type, and click “Add”.
5. Leave the entry for domain name blank, and enter the name of the first nameserver (e.g. ns1.nsdomain.com). Click OK.
6. Repeat steps 4 and 5 for the second nameserver (e.g. ns2.nsdomain.com).
7. In Add a DNS Record, choose A for record type, and click “Add”.
8. In domain name, enter the subdomain of the first nameserver (e.g. ns1) in the blank, and enter the IP you are assigning to
this nameserver in the 4 blanks for the IP address. Click OK.
9. Repeat steps 7 and 8 for the second nameserver.
10. Click Server in the System section of the left navigation bar.
11. In the Services section, click DNS.
12. Check the box in the line with the NS record. Click “Remove Selected”.
13. Check the box to confirm removal. Click OK.
14. In Add a DNS Record, select NS for record type, and click “Add”.
15. Leave the entry for domain name blank, and enter the name of the first nameserver (e.g. ns1.nsdomain.com). Click OK.
16. Repeat steps 14 and 15 for the second nameserver (e.g. ns2.nsdomain.com).
17. At this point, the nameservers are configured on your server, and you will need to register the nameservers with your domain
registrar. Please refer to your domain registrar for further instructions on how to do this.