Minecraft wiki entry for Name_Tag, associated text: Using a name tag on a villager renames the villager instead of opening the trading interface. A saddled pig is renamed instead of being ridden. Using a name tag on any other mob that can be interacted with performs the use action instead of being named. These mobs can be renamed if the player uses the name tag while crouching or standing in a nether portal because the portal suppresses the use action.