Can I use same IPs as resolver and nameserver on my WHM Server?

Umm, before answering this question, I should say I get the very distinct impression by the way you wrote your message that you really don't entirely understand what exactly "resolvers" are in the context of the options shown in WHM because those actually have nothing to do with the DNS resolution of your domain names whatsoever -- totally different subject.

Your question is kind of an "apples and "oranges" type of question mixing two different topics together. However, this is a very common mistake among new Cpanel/WHM users so you aren't the only one out there to ever get a little confused about this particular topic.

The resolvers (IE: those listed in /etc/resolv.conf and WHM) is the list of DNS server addresses that your server uses for OUTBOUND communication when it needs to connect to some other server on the internet. The servers named as "resolvers" is the DNS servers that your server uses to be able to find other sites on the internet.

For example, say you run "/scripts/upcp" to update update your Cpanel with the latest updates. Your server needs to connect to some other server out on the internet to go download the latest Cpanel updates. The servers in the resolvers list are then used to find out what IP your server needs to connect with to go get those updates, etc.

The resolvers have ABSOLUTELY NOTHING to do with the resolution of your own domain names.

Typically, the resolvers are set to large public DNS servers, a few real working examples:

Code:

nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 4.2.2.1

(Side footnote: Unlike DNS, the external resolvers are never IP numbers from your own server)

Now the NS1.yourdomain.COM and NS2.yourdomain.COM you setup for other computers on the internet to be able to find your domain names is something you setup in your main domain's DNS record and also at the registrar where you purchased your domain and that is so that other servers and people out on the internet can reach your domains and you do not do anything with the "resolvers" list in WHM to setup any of that.

To put this all in the simplest context, just think of it this way:

RESOLVERS are for OUTBOUND[/b[ communications that your server uses to resolve and connect to other servers on the internet.

DNS (IE:NS1/NS2 that you setup on for your domain name) is for INBOUND communications that other servers out on the internet use to communicate back to you and with reaching your domain names.

As you can see, those are two totally distinct and different subjects entirely and are actually completely opposites since one deals with your server connecting to other places on the internet and the other deals with other people on the internet connecting to your sites.