Place hash browns, eggs, sour cream/Greek yogurt, dill, chives, garlic powder, salt, onion powder and black pepper in a large bowl. Mix until completely combined. Heat oil in a large nonstick or cast iron skillet. Place dollops of hash brown mixture into hot skillet. Allow to cook 2-3 minutes on each side, or until crispy on each side. Repeat with remaining mixture. Coat a medium frying pan with cooking spray and heat to medium. Crack eggs into the pan once it's hot and season with salt and black pepper. Allow to cook for a few seconds, then turn heat down to medium-low. Allow to cook until egg white is almost set, then put a lid on the pan and turn to low. Cook just until top of the white is set, but yolk is completely uncooked. Place eggs on crispy hash brown haystacks and serve with green onion or sour cream/Greek yogurt.