After playing reactions to buff a card during Showdown, can an opponent play an action when priority passes back to them?

Ruling: Yes, if there is a Showdown active, your opponent can play an action when priority passes back to them.

Sequence:

• You play your reactions to buff a card
• The reactions resolve (chain ends)
• Priority passes back to your opponent
• Your opponent can start a new chain by playing an action
• Showdown only ends after all players pass in succession without starting a chain

Nuances:

• Multiple chains can occur within the same Showdown
• This only applies during Showdown; the ability to respond depends on whether Showdown is active