How can filter a view by several NID's?
You will need to add contextual filters in the view.


Just go to advanced -> contextual filter -> add new 'content:nid'
field.
Check 'profile default value' option from list entitled 'WHEN THE FILTER VALUE IS NOT AVAILABLE' -> Choose 'Fixed value' option and add multiple nids seperating them via '+' e.g. 1+2+3
Then from 'more' fieldset check on 'allow multiple values' option.


This should do it. You can check also in sql query generated by view below it which should show something like this in where clause e.g. WHERE (( (node.nid IN('1', '2', '3') ) )