When Traveling Merchant moves to Zaun Warrens and triggers Showdown, and I discard Flame Chompers as part of the Merchant's trigger, what is the timing/order of resolution?

Ruling: When Traveling Merchant moves and triggers both its ability and Showdown, you fully resolve the Merchant's trigger (including discarding and drawing) before Flame Chompers' discard trigger goes on the chain. You can never interrupt a resolving effect in Riftbound.

Sequence:

• Move Merchant, Showdown stages, Merchant's move trigger goes on chain
• Pass priority, chain resolves: discard and draw happens
• Discarding Chompers triggers here and goes on chain
• Pass priority, Chompers' "when you discard me" trigger resolves, Chompers goes on chain
• Chompers resolves
• Chain empty, staged Showdown starts

Nuances:

• If Merchant is killed while its move trigger is on the chain, the trigger still resolves fully (discard still happens) because the resolution is not tied to the unit surviving
• Some abilities specify "here" and would resolve to no effect if the unit moves/dies, but Merchant's does not care where it is