Module provide nominatium geocoder to geolocation_leaflet module
When you choose a widget Geolocation Leaflet - Geocoding and Map in form display area and click settings
you can choose for LEAFLET SETTINGS area Gecoder plugin. This module add new geocoder Nominatim.
This module depend on geolocation 2.x, module provide geolocation_leaflet module require by this module.
Install
composer require 'drupal/geolocation:2.x-dev'
composer require 'drupal/geolocation_nominatim'