Final answer:
The nursing intervention that most completely meets the client's needs in managing diverticulitis after discharge is providing education on dietary modifications and lifestyle changes.
Step-by-step explanation:
The nursing intervention that most completely meets the client's needs in managing diverticulitis after discharge is providing education on dietary modifications and lifestyle changes. The nurse can explain the importance of a high-fiber diet to prevent constipation and the formation of new diverticula. Additionally, the nurse can teach the client about the importance of staying well-hydrated and engaging in regular exercise to maintain bowel regularity.