Final answer:
The best nursing action in response to a terminally ill client expressing being an agnostic is to offer to contact a spiritual advisor of the client's choice and document the statement in the client's spiritual assessment.
Step-by-step explanation:
The best nursing action in response to the terminally ill client expressing being an agnostic is to offer to contact a spiritual advisor of the client's choice. This shows respect for the client's beliefs and provides an avenue for spiritual support if desired. Documenting the statement in the client's spiritual assessment is also appropriate to ensure that this information is included in the client's care plan.