NICOP IS dual-nationality. NICOP is just a CNIC where "country of stay" is some country other than Pakistan.
So really two questions:
1) Is there any advantage of having a passport in addition to NICOP. NO.
2) Should you renounce Pakistani citizenship and get a POC card instead. Up to you. The main reason people do this is if they are very wealthy - Pakistan has reduced the definition of tax residence to only 4 months for Pakistani citizens, and Pakistani tax authorities are starting to get very aggressive. So if you have a lot of assets, getting a POC card instead of NICOP might have an advantage. Otherwise, don't bother.