Heat olive oil in a large pot and cook onion until soft and translucent, about 5 minutes. Add pine nuts and garlic and briefly saute, about 2 minutes. Add chard and saute until slightly wilted, about 3 to 5 minutes. Add raisins, white wine, and lemon juice; cover and cook on low heat until chard is soft and wilted, about 5 to 10 minutes. Season with salt and pepper.