views contextual filter based on NID that is selected from a list I have a slideshow in front page build by with Views and placed by Panels.

Currently i'm using contextual filter based on Nid and end user should enter Nids in Panels pane setting like "6,14,54,98" but it's not user friendly.

I need a list of nodes that end user can select nodes and the list automatically returns Nids.
You can use Nodequeue module for this. Quote from its project page:

The Nodequeue module allows users to collect nodes in an arbitrarily ordered list. The order in the list can be used for a any purpose, such as:

A block listing teasers for the five top news stories on a site
A user’s favorite music albums
A group of favorite from which one is randomly displayed

Nodequeue provides a simple drag-and-drop interface to manually order any queue. Additionally, it allows nodes to be added and removed from queues without needing edit permissions to the node. Nodes can be added to queues either from a queue management tab or by links on the node teaser.