Can you play another action after a chain is resolved to start another chain during a showdown, and who gets priority to start the second chain?

Ruling: Yes, you can play multiple actions during a showdown by starting new chains. After each chain resolves completely, "Focus" (the opportunity to play an action/start a chain) automatically passes to the next player.

Sequence:

• During a showdown, if there is combat, the attacker gets focus first; if the battlefield is open, the player who contested it gets focus first
• When a chain resolves, focus automatically passes to the opponent
• The opponent can then play an action (starting a new chain) or pass
• If they pass, focus returns to the original player who can play an action or pass
• Both players must pass consecutively (back-to-back) for the showdown to end
• If either player plays an action after the other has passed, focus continues alternating until both pass consecutively

Nuances:

• While you hold Priority (opportunity to play reactions) when adding an item to the chain, focus always automatically passes when the chain has resolved
• You cannot play multiple actions in a row without focus passing to your opponent between chains