Brown the ground beef in a large skillet over medium-high heat, breaking it into crumbles. Add diced onion and cook until softened, about 5 minutes. Stir in minced garlic and cook 1 minute more. Drain excess fat.

Layer the potatoes in the bottom of your 6-quart slow cooker. Arrange sliced potatoes in an even layer, slightly overlapping if necessary.

Add the beef mixture over the potatoes, spreading it evenly. Top with drained kidney beans and corn.

Pour the diced tomatoes with their juices over the beef and bean layer.

Whisk together the cream of mushroom soup, beef broth, chili powder, smoked paprika, garlic powder, salt, and pepper in a mixing bowl until smooth.

Pour the soup mixture evenly over all layers in the slow cooker.

Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, until potatoes are tender when pierced with a fork.

Sprinkle shredded cheddar cheese over the top during the last 30 minutes of cooking. Cover until cheese is melted.

Let rest for 10 minutes before serving. Garnish with sour cream and sliced green onions if desired.