To get a field off of a particular child relationship record:
{{$Model.NYItemMaster.data.0.SCMC_InventoryItems__r.records.0.SCMC__Condition_Code__r}}
To get a field off of a particular child relationship record:
{{$Model.NYItemMaster.data.0.SCMC_InventoryItems__r.records.0.SCMC__Condition_Code__r}}