Variable in module.exports properties?

I want to dynamically create properties in a module.export.

for (var i = 0; i < jsonSettings.length; i++) {
    for (var key in jsonSettings[i]) {
        module.exports = {
            key: nconf.get(key)
        }
    }
}

How do I get the 'key' part to not come up as 'key' for the property name, but actually be the value of key?

Full Code:

var fs = require('fs'),
    nconf = require('nconf');

var defaultSettingsPath = __dirname + '/settings.json';

nconf.env().argv();
nconf.file('settings', { file: 'settings.json', search: false });
nconf.file('defaults', { file: defaultSettingsPath});

fs.readFile(defaultSettingsPath, function (err, settings) {
    var jsonSettings = (settings.toString());

    for (var i = 0; i < jsonSettings.length; i++) {
        for (var key in jsonSettings[i]) {
            module.exports = {
                key: nconf.get(key) 
            }
        }
    }
});