How Can I use different node as a nodelet in my pkg?
Nodes cannot be used as nodelets. So what you ask is not supported right now.
Whether something is a node or a nodelet is a programming-time decision (ie: there are different ways in which you create a node or a nodelet). This cannot be changed in ROS 1.
If however you are asking whether it's possible to load a nodelet from another package, then that would be fully supported. If you could clarify we can address that question.
Edit:
So, it means: one nodelet manager = one pkg. Cannot include nodelet from other pkg?
from your edit it would appear you're actually interested in loading nodelets from other packages.
That is fully supported. Nodelets are "just" plugins (literally: they're stored in .so
(shared libraries)).
As long as the nodelets you want to load into a manager are on the search path (ie: part of your workspace, or any of its underlays) you can load them.