Preheat oven to 375°F (190°C) and grease a casserole dish.
Heat olive oil in a large skillet over medium heat.
Add diced onion and cook until soft and translucent.
Stir in minced garlic and cook for about 30 seconds.
Add ground beef and cook until browned breaking it apart as it cooks.
Stir in diced tomatoes, corn, potatoes, ketchup, mustard, smoked paprika, salt, and black pepper.
Cook the mixture for about 5 minutes until well combined.
Transfer the beef mixture to the prepared casserole dish.
Spread sour cream evenly over the top.
Sprinkle shredded cheddar and mozzarella cheese over the casserole.
Top with crushed tortilla chips or fried onions for crunch.
Bake for 20–25 minutes until cheese is melted and bubbly.
Garnish with chopped parsley before serving.