Mix powdered buttermilk, garlic powder, parsley, sugar, salt, and onion powder together in a small bowl until combined.
Place frozen waffles in a bowl. Drizzle with olive oil and toss to coat. Sprinkle with sour cream and onion mix and toss to coat evenly. Spread waffle fries in a single layer on a baking sheet.
Bake in the preheated oven until lightly golden and crispy, 20-26 minutes, or according to package directions.
Meanwhile, place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon on a paper towel-lined plate. Crumble and set aside.
Remove waffle fries from the oven and sprinkle evenly with Cheddar cheese and crumbled bacon.
Return fries to the oven; bake until cheese is melted, about 3 minutes. Top with green onions and sour cream. Serve immediately.