Yes. You just need to insert an action (*.instance) into the folder Loaders/text/x-java/Actions/ in your module's XML layer. (Available in NetBeans 4.1 and later only.)
In any version of NetBeans, you can also add a global "tools" action to your module's manifest, which will appear in the Tools submenu of the context menu of any node to which the action applies (i.e. on which it is enabled).
Source: NetBeans FAQ