Preheat and Cook Tater Tots:
Preheat the oven to 425°F (220°C). Spread tater tots on a baking sheet and bake according to package instructions until crispy. Set aside.

Cook the Macaroni:
Bring a large pot of salted water to a boil. Add the elbow macaroni and cook until al dente, about 8-10 minutes. Drain and set aside.

Cheese Sauce:
In a medium saucepan, melt butter over medium heat. Whisk in flour and cook for about 1 minute until the mixture is bubbling and lightly golden. Gradually add the milk, whisking constantly until the mixture thickens. Stir in the cheddar and Parmesan cheese until melted and smooth. Add garlic powder, onion powder, mustard powder (if using), salt, and pepper. Adjust seasoning to taste.

Combine Ingredients:
Gently fold the macaroni into the cheese sauce until all pasta is well coated. Set a portion of tater tots aside for topping and gently mix the rest into the macaroni and cheese.

Assemble and Bake:
Preheat the oven to 375°F (190°C) if needed. Grease a baking dish with cooking spray or oil. Pour the macaroni and tater tot mixture into the dish. Sprinkle reserved tater tots on top. (Optional) Sprinkle breadcrumbs over the top for extra crunch.

Bake:
Bake in the oven for about 15-20 minutes, or until the top is bubbly and golden brown.

Serve:
Remove from the oven and let it cool slightly. Garnish with chopped chives before serving.