I have Heedless Resurrection as my only card in hand after playing Fizz, I play Lunar Boon off the Fizz effect in the trash, can I chain Heedless Resurrection to it and still draw 2?

Yes, you can successfully draw two cards by playing Heedless Resurrection in response to Lunar Boon when triggered by Fizz, Trickster.

The Sequence of Events

1. Fizz, Trickster triggers: You have played Fizz, Trickster. His "When you play me" ability is on the chain. The game state is Closed.
2. Play Lunar Boon: You use Fizz's triggered ability to play Lunar Boon from your trash. It is played as part of the resolution of Fizz's ability.
3. Chain Heedless Resurrection: You play Heedless Resurrection from your hand in response to Lunar Boon. As a [Reaction] spell, it is a legal play in this Closed State and is added to the top of the chain.
4. Chain Resolution (LIFO):
   • Resolution 1: Heedless Resurrection resolves first. You pay the cost (killing a friendly unit) and resurrect your chosen unit from the trash.
   • Resolution 2: Lunar Boon resolves next. Per FAQ #9952, because the discard is part of the effect and not a cost, you can still resolve the spell even if you have no cards in hand. You discard zero cards and successfully draw two cards.
   • Resolution 3: Finally, Fizz's triggered ability finishes resolving.

Key Considerations

• [Reaction] Keyword: Rule 813.1.c grants cards with the [Reaction] keyword the ability to be played during Closed States.
• DAMAYC (Do As Much As You Can): As clarified in RiftJudge FAQ #9952, Lunar Boon does not require a hand discard as a cost; therefore, even with an empty hand, the effect resolves as far as possible, allowing you to draw two cards.

Note: I could not fully verify the existence of the [Reaction] keyword on these specific cards against the retrieved rules.