I believe the Visualization supports only 1 layer from PBI data at a time. The other layer will need to be published to Portal or AGOL and added as a reference layer.
Hey there @CameronFrancis ! @KevinDunlop is correct in their statement. Currently, only one Power BI data layer can exist on the map. We are looking to improve this functionality in the future to support more than one data layer on the map.
Once we have it sorted out, we will make an announcement on the forums and details on how to it up and running!