How to add scoreboard value to a certain item entity [post 1.13]

Solution 1:

It's directly in selector arguments now. So you could use this:

scoreboard players set @e[nbt={Item:{id:"minecraft:flint",Count:1b,tag:{display:{Name:"TMNextStage"}}}}] TMNextStage 1

But you could also directly do things for them, for example like this:

tp @e[nbt={Item:{id:"minecraft:flint",Count:1b,tag:{display:{Name:"TMNextStage"}}}}] @s

Also, if you add type=item to the selector, performance improves, because Minecraft doesn't need to check the NBT of every entity.