Slow Cooker Cornbread Casserole - No Getting Off This Train

Ingredients

• 1 yellow onion
• 1 bell pepper, any color
• 1 clove garlic, minced
• 1 tablespoon olive oil
• 1 can kidney beans, drained and rinsed
• 1 can pinto beans, drained and rinsed
• 1 8-oz can tomato sauce
• 1 15-oz can diced tomatoes
• 1 tablespoon chili powder
• Salt and pepper, to taste
• 1 box Jiffy cornbread mix
• 1 can corn, drained and rinsed