Place the onion, oil, and garlic in the inner cooking pot. Press the COOK SWITCH and sauté for 3 minutes. Use a large wooden spoon to gently stir as the onion and garlic cook. Add the chili, salsa, cream cheese, and cheddar cheese. Stir to combine all of the ingredients, and place the lid securely onto the rice cooker. Cook for 4 minutes. Carefully open the lid, keeping hands and face away to avoid steam, and stir the dip. Cook again for 3 minutes. Open the lid and stir again. Continue cooking until the dip is warm throughout and the cheeses are melted. When done, serve in a large bowl and use the tortilla chips for dipping. Serves 4.