In a large saucepan, heat olive oil.
Add onion, celery and jalapeƱo and cook to soften; about 15-20 minutes.
Add swiss chard. Stir to mix, and season with salt and pepper to taste.
Cover and simmer over low heat until chard is tender; about 10 minutes.
Stir in half-and-half and swiss cheese and cook until cheese is bubbling.