If a spell is countered, can the Jhin legend still have the spell banished for its ability?

No, you cannot banish a spell with the legend ability of Virtuoso (Jhin) if that spell has been countered.

According to Rule 425.1.b, a card that is countered is not considered to have been played. Because Virtuoso’s ability explicitly requires you to "play a spell" to trigger, a spell that is countered fails to meet the condition required for the ability to trigger.

Furthermore, per Rule 425.1.a, a countered spell is immediately cleared from the chain. Since the spell is no longer on the chain, it cannot be targeted or banished by Virtuoso’s ability even if the trigger condition were met.

The Sequence

1. Playing the Spell: You play a spell and pay its costs. It is placed on the chain as a Finalized Chain Item.
2. Reaction: Your opponent plays a card (like Defy) to counter your spell.
3. Resolution: The counter resolves, and your spell is cleared from the chain.
4. Trigger Check: Because the spell was countered, it is not considered to have been "played" for the purpose of triggering "When you play a spell" effects. Consequently, Virtuoso's ability does not trigger.

This interpretation is supported by RiftJudge FAQ #9779, which clarifies that a countered spell cannot be banished by Jhin's effect because it is not considered played and is removed from the chain.