Does Tide Turner have to choose targets to get put on the chain?

Yes, Tide Turner must choose a target to put its "When you play me" ability on the chain.

According to FAQ 6775 and FAQ 7573, you must choose targets during the activation of the ability (when the trigger is placed on the chain) before opponents can react. If you choose to use the "you may" ability, the target must be declared at the moment the trigger is initiated.

Key Clarifications:

• Trigger Category: As defined in Rule 383.4.a and 383.4.a.1, Tide Turner’s "When you play me" ability is a Play Effect.
• Timing of Choices: Contrary to general triggered abilities, FAQ 6775 specifies that for Tide Turner, you choose required targets as part of the activation process, occurring when the trigger is placed on the chain.
• Ability Initiation: Because the ability is phrased as "you may," it is optional. You may choose to play Tide Turner without placing the triggered ability on the chain; however, if you do choose to activate it, you must declare the target immediately upon placing it on the chain.

Note: This ruling is based on the provided FAQs, which override general rule interpretations regarding the timing of target selection for this specific unit.