Loaded Tater Tots

Name: Loaded Tater Tots
Ingredients: 1 (32 ounce) package frozen bite-size potato nuggets (such as Tater Tots®); 4 slices bacon; 2 tablespoons butter; 1 shallot, minced; 2 tablespoons all-purpose flour; 1.5 cups whole milk; 2 tablespoons sour cream; 1 pinch ground black pepper; 1 pinch nutmeg; 1.5 cups shredded sharp Cheddar cheese, divided; 3 green onions, sliced; 2 tablespoons sour cream, or to taste