Heat the olive oil in a large skillet over medium high heat. Add the ground turkey and cook, breaking it up with a wooden spoon, for 5-7 minutes until fully browned. Transfer the turkey to a 6 quart slow cooker.
To the slow cooker, add the diced onion, chopped red and yellow bell peppers, tomato sauce, diced tomatoes (with juices), rinsed black beans, rinsed kidney beans, drained jalapeƱos, frozen corn, chili powder, and cumin. Stir thoroughly to combine.
Season generously with salt and black pepper. Cover with the lid.
Cook on HIGH for 4 hours or on LOW for 6-8 hours.
Once cooked, give the chili a final stir. Serve hot in bowls with your choice of optional toppings.