Sour Cream Streusel Coffee Cake

Name: Sour Cream Streusel Coffee Cake
Cuisine: European, German
Ingredients: 1/4 cup Cinnamon Sugar; 1/2 cup Pecans or Walnuts, chopped; 2 cups All-Purpose Flour; 1 teaspoon Baking Powder; 1 teaspoon Baking Soda; 1/2 cup (1 stick) Unsalted Butter, room temperature; 1 cup Granulated Sugar; 2 Large Eggs, room temperature; 1 1/2 teaspoons Vanilla Extract; 1 1/4 cup Sour Cream (full fat); 8 ounces Cream Cheese, softened; 1/2 cup Confectioners Sugar; 1 tablespoon Vanilla Extract; 3 teaspoons Unsalted Butter, melted; 1/2 cup Whole Milk