Heat butter in a skillet over medium heat and add diced potatoes. Cook until golden brown and crispy, about 8-10 minutes.
In a bowl, whisk eggs, milk, salt, black pepper, and garlic powder.
Reduce heat to low and pour the egg mixture over the potatoes. Stir gently until eggs are cooked through, about 3-4 minutes.
Sprinkle shredded cheddar cheese over the scramble and let it melt.
Garnish with chopped green onions and serve immediately.