Setting a single valued taxonomy column from a combo box

PowerApp.Patch.Single.MMD.js

// Where 'My Document Library Name' is the name of your document library / list
Patch('My Document Library Name', {
  // Where 'MyInternalTaxonomyFieldName' is the internal name of the Managed Metadata column in SharePoint
	MyInternalTaxonomyFieldName: {
             // Where MyComboSelectBox is the single select combo box containing the selected choice in your Power App
	     '@odata.type':"#Microsoft.Azure.Connectors.SharePoint.SPListExpandedTaxonomy",
	     TermGuid: MyComboSelectBox.Selected.TermGuid,
	     WssId: MyComboSelectBox.Selected.WssId,
	     Label: MyComboSelectBox.Selected.Label,
	     Path: MyComboSelectBox.Selected.Path,
	     Value: MyComboSelectBox.Selected.Value
    }
    // Each of your other fields would be comma separated below...
});