I will update nameserver or changeitfor two domains for 1 gig. Why do you need to update nameserver or need changing DNS settings?
If your domain is registered from another company rather than your hosting company, you need to update it with your current hosting. Similarly if you have changed or going to change the hosting to another company then changes are required. Again if your domain and hosting is from the same company and you want to transfer the domain or hosting keeping another then you need to change it and need to update it. It point the domain to the location where your files are uploaded. Also there is an another option in hosting server to point the domain to a specific directory, where the files are located. By default domains are pointed to the root directory. What do you need to provide? Login credentials for the account where your domains are currently registered (not c-panel or hosting) C-panel/hosting account access is required if it required to modify DNS records. The list of new nameservers need to add there (more preferred) or ask me before you order this gig, I may find this for you.
If you want to know more or something else, please contact me first.