Minecraft wiki entry for Chest, associated text: Block entity data
Tags common to all block entities[show]
 CustomName: Optional. The name of this container in JSON text component, which appears in its GUI where the default name ordinarily appears.
 Items: List of items in this container.
: An item, including the slot tag. Chest slots are numbered 0-26, 0 starts in the top left corner.
Tags common to all items[show]
 Lock: Optional. When not blank, prevents the container from being opened unless the opener is holding an item whose name matches this string.
 LootTable: Optional. Loot table to be used to fill the chest when it is next opened, or the items are otherwise interacted with.[note 1]
 LootTableSeed: Optional. Seed for generating the loot table. 0 or omitted use a random seed.[note 1]