QGIS3 Atlas: expression to pull values from a non-coverage layer at current location?

Question

I have an atlas composition where I would like to, in addition to attributes from my coverage layer which consists of polygons that are scattered throughout the world, place other values from another layer.

I would like an expression in a text box that displays the name of the country that the current feature is in.

Answer 1

I found an answer based on she_weeds' excellent answer in How to display attributes of features intersecting the Atlas feature in a Print Composer label?

Having downloaded and imported Natural Earth's country .shp file as a new layer, I used the aggregate function to get the country name containing the current feature's geometry.

[% aggregate(
    'ne_10m_admin_0_sovereignty',
    'concatenate',
    "NAME_EN",
     contains($geometry,@atlas_geometry), 
    ','
   ) %]