Does Jinx, Loose Cannon's ability trigger and open a chain that can be reacted to?

Ruling: Yes, Jinx's ability is a trigger that opens a chain and can be reacted to. You can recognize triggers from the words "when" or "at".

Sequence:

• Beginning phase starts
• Jinx trigger creates a chain as link 1
• Opponent can react (e.g., with cards like Gust as chain link 2)
• Chain resolves in reverse order
• When Jinx trigger resolves, it checks the condition at that time (if opponent bounced a unit to bring hand to 2 cards, Jinx does not draw)

Nuances:

• Jinx always triggers every turn at the beginning phase
• The trigger checks hand size when it resolves, not when it triggers, so opponents can respond to prevent the draw by bouncing a unit to the Jinx player's hand
• This happens before hold scoring, so there is always an opportunity to react against Jinx before she would hold, regardless of her hand size