NBT, or Named Binary Tag, is the data of a block or item that is changable using inventory editors, like Horion and MCEdit. A different way of explaining it is to say it is how minecraft stores item/block data. Using Horion, you need to copy text from either a message or a file downloaded from online containing the correct Horion NBT format.
First, lets explain what I mean by “NBT type”. There are .nbt load and .nbt write NBTs. .nbt load NBTs are NBTs that create an item, which is specified in the text, and replace the current slot with it. .nbt write NBTs do NOT create an item, and simply overwrite the tags, like enchantments and names, of the item being held. This means that doing both .nbt write and .nbt load on the same nbt is useless, and will replace the first item with the second item anyways.
A simple example of the different nbt types are below
.nbt load
{Count:64b,Name:"wooden_sword",tag:{Unbreakable:1b}}
or
.give wooden_sword 1+.nbt write.give wooden_sword 1 0 1 (the 1 means the same as .nbt write)
{Unbreakable:1b}
The difference between how you can use these NBTs is kinda big. For .nbt load, you only get the wooden sword with the unbreakable tag, and thats it. Although, with .nbt write, you can give yourself any breakable item, do .nbt write, and then it will be indestructable. So, as a recap, an NBT that starts with a tag, like {ench:[ is a .nbt write NBT, and an NBT that starts with an item, like {Count:1b,Name:" or {{Items:[ (notice the extra bracket) is a .nbt load NBT.
NBT tags are what give items effects, like enchantments, names, and entities. There are many tags, and even tags in tags, which will come in a bit later.
tag:{tag:{