iNatuarlist’s standard widget displays observations for a given user, place, or project. so if you want to use that standard widget, i think the closest you can get is to create a project that mimics the list, and then display the observations in that project.
otherwise, it is possible to query by list:
and then if you are able to do some coding, you could make your own widget using the API. for example: https://jumear.github.io/stirfry/iNat_observation_grid_widget.html?list_id=111820&rows=4&columns=3&place_id=57482