Cook chopped bacon in a skillet over medium heat for 5–7 minutes until crispy. Transfer to a paper towel–lined plate and reserve 1 tablespoon of bacon grease.
In the same skillet, brown ground beef with diced onion for about 7 minutes. Drain excess fat if needed, then stir in garlic, ketchup, mustard, Worcestershire sauce, smoked paprika, salt, and pepper. Cook 2 more minutes.
Boil ramen noodles (discard seasoning) for 2 minutes, keeping them slightly undercooked. Drain and set aside.
Whisk condensed cheddar soup, sour cream, and milk in a large bowl until smooth. Stir in shredded cheddar, mozzarella, ramen, beef mixture, and half the bacon.
Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish. Spread the mixture evenly, top with remaining cheddar, crushed tortilla chips or bread crumbs, and the rest of the bacon.
Bake for 20–25 minutes until the cheese is bubbly and melted. Rest 5 minutes before serving. Garnish with green onions if desired.