Free Heroes of the Storm In-Game Loot - Twitch Prime/Amazon Prime Members
Twitch Prime Members:
Heroes of the Storm: Legendary Loot Chest Free
Login to your Twitch account and you can see it in the prime loot box.
Amazon Prime member is also required, if you are not you can start the 30-day free trial via the link they give you.
Note: Twitch Prime is included with your Amazon Prime Membership.
Available from Apr 2 – May 1, more loot chest is coming on May and June