Place the diced eggplant, zucchini rounds, chopped bell pepper, diced onion, and minced garlic into the slow cooker.
Add the diced tomatoes with their juices and the drained chickpeas.
Drizzle in the olive oil, then sprinkle the oregano, dried basil, salt, and black pepper over the top.
Stir gently to combine all ingredients evenly.
Cover and cook on low for 6 to 7 hours, until the eggplant is very tender.
Ladle into bowls and top each serving with a few fresh basil leaves.