Hey,
I would suggest you dont run your own nameservers.
Go to GoDaddy, select your domain and click on "manage dns zones". Change the A record to your server IP. Save.
On Plesk you can now add your domain.
Your website should now resolve to your VPS.
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Added after 4 minutes:
Btw do not change your NS records to anything.. Keep the GoDaddy domaincontroll ones.
If you do have a dns server running, do the same as my post above, except go to "hostnames" and add ns1 and ns2 pointing to your IP. Then change your dns zone ns records to ns1.yourdomain and ns2.yoursomain. This on the other hand will take about 6 hours to resolve.