For the muffins:
Preheat the oven to 400 degrees. Line twelve muffin cups with cupcake liners; set aside.
In a large mixing bowl stir together flour, baking powder, and kosher salt. Fold in the mini chocolate chips. Make a well in the center of the flour mixture and set aside.
In a medium mixing bowl combine the eggs, sugar, milk, orange zest, orange juice, and vegetable oil. Take the egg mixture and add it to the flour mixture all at once. Stir until combined and it’s okay if the batter is kind of lumpy.
Spoon about 1⁄4 cup of the batter into each muffin cup. Top each muffing with the streusel topping and bake for about 18 to 20 minutes. Cool the muffins on a wire rack before serving!
For the streusel topping:
In a small food processor add the flour, sugar, and butter. Pulse until the mixture resembles coarse crumbs. Pour the mixture into a bowl and stir in walnuts or pecans, and mini chocolate chips.