Updating your domain nameservers in namecheap is pretty simple. Before you go ahead make sure you’ve got your new nameservers ready to input!
Access the Domain Manager by clicking on the Account menu option then Domain List.
Click Manage on the domain you want to manage.
Scroll down in the Domain section of the Domain Manager until you see the Nameservers label. Click the Nameservers dropdown.
Choose Custom DNS from the dropdown.
Enter your new nameservers in the text boxes. To add additional nameservers click the + Add Namerserver button.
Once all your nameservers have been added click the green tick to save them.
Namecheap will give you a message letting you know that you’ve successfully updated the nameservers and warning you it could take up to 48 hours for the changes to take affect.
Even though namecheap say it’ll take up to 48 hours in my experience the changes usually take affect anywhere from a few minutes to a few hours after making the changes.
That’s it! Now you just need to patiently wait for the nameservers to update. If you go to your websites url and it hasn’t updated then try clearing the cache or checking from a different browser/device. Sometimes your browsers cache will keep showing you the old page even after the nameservers are updated.