Use default application as file thumbnail in Mint's file browser

In Mint's default file browser (which is Nemo, as far as I know), I'd like to set the icon of the default application for a certain file type as the thumbnail for all files of this file type. For example I'd like all .odt files to have the icon of the LibreOffice Writer as their thumbnail, and all .pdf files to have the icon of the respective PDF editor. What is the best way to accomplish this?