How to configure Node Export to mass node export? I'm trying out Node Export for mass node export, but it seems that I have to choose every node to export individually.

What if I want to export all nodes of a selected content type? Is there any way I can do this in Node Export, or I should find another module?
You can do it with drush:

$ drush help ne-export
Export nodes using Node export.

Arguments:
  nids : A list of space-separated node IDs to export.

Options:
  --file : The filename of the output file.  If supplied, the node code will be
exported to that file, otherwise it will export to stdout.
  --format : If supplied, node code will be output using a particular export
format, if available. (e.g. serialize)
  --status : Filter for 'status'; A boolean value (0 or 1) indicating whether
the node is published (visible to non-administrators).
  --promote : Filter for 'promote'; A boolean value (0 or 1) indicating whether
the node should be displayed on the front page.
  --sticky : Filter for 'sticky'; A boolean value (0 or 1) indicating whether
the node should be displayed at the top of lists in which it appears.
  --translate : Filter for 'translate'; A boolean value (0 or 1) indicating
whether the node translation needs to be updated.
  --language : Filter for 'language'; The language code (e.g. de or en-US) of
this node.
  --type : Filter for 'type'; The machine-readable name (e.g. story or page) of
the type of this node.
  --sql : Filter by SQL (EXPERIMENTAL); An SQL query string that returns nids
(e.g. "SELECT nid FROM nodes WHERE nid &lt; 10").
  --code : Filter by PHP code (EXPERIMENTAL); PHP code that prints or returns,
an array or CSV string of nids (e.g. "custom_get_my_nids();"). Don't include PHP
tags.


For example, 

drush ne-export --type=article --file=article.txt


will output all of the article nodes to article.txt in serialized format.  You can then use drush to import them:

$ drush help ne-import
Import nodes previously exported with Node export.

Arguments:

Options:
  --uid : User ID of user to save nodes as. If not given will use the user with
an ID of 1. You may specify 0 for the Anonymous user.
  --file : The filename of the input file.  If supplied, the node code will be
imported from that file, otherwise it will import to stdin.


For example:

drush ne-import --uid=1 --file=article.txt

*updated