Changed Permalinks settings, how do I redirect posts on Nginx?

Using the Simple 301 Redirects Plugin

You can download the plugin from the WordPress.org repository here. Once you have installed and activated the plugin it adds a new menu to the Settings area of your dashboard.

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There really isn’t a great deal to worry about with this plugin. In the 301 Redirects settings window you are shown two simple fields. One is labeled Request and the other Destination. This is basically where you enter the old permalink structure and the new permalink structure. You only need to add the information after your domain name to these fields.

In the example in the image above, the Request field is the WordPress configuration for the Month and Name permalinks while the Destination field is the WordPress configuration for the Post name permalink structure. Once you have added these two fields, save the changes. This will now tell any search engine traffic that comes into the old links where to go.

Reference : http://www.wpexplorer.com/change-permalinks-wordpress/