Add the potatoes, corn, onion, flour, chicken broth, garlic powder, salt, and pepper to a 6-quart slow cooker. Stir to combine.
Cover and cook on high for 4 hours or on low for 6-8 hours, until the potatoes are tender.
In a small bowl, whisk together the heavy cream and 3 tablespoons of the hot liquid from the slow cooker until smooth. Pour the mixture into the slow cooker and stir to combine.
Add the butter and stir until melted.
Cook on high for an additional 30 minutes, or until the chowder has thickened to your liking.
Stir in the chopped bacon.
Serve hot, garnished with additional bacon, shredded cheese, and chopped green onions if desired.