Chop and add your onion to the bottom of a large 6-quart slow cooker or crockpot. Turn the slow cooker on high while you prep the rest of the ingredients.
Open, drain, and rinse your beans and corn before adding them and the rest of the ingredients to the slow cooker. Mix everything together to combine.
Cover the slow cooker and cook on low for 5-6 hours or high for 3-4 hours.
