Preheat oven to 425°F. Toss diced potatoes with olive oil, smoked paprika, garlic powder, onion powder, salt, and pepper directly on a large rimmed sheet pan. Spread into a single, even layer.
Roast for 30–35 minutes, flipping halfway through, until deeply golden and crisp at the edges.
While the potatoes roast, heat a large skillet over medium-high heat and add the ground beef. Break it up with a spatula and cook for 6–8 minutes, until no pink remains.
Drain excess grease. Add taco seasoning and water to the skillet. Simmer for 3–5 minutes, stirring occasionally, until thickened and glossy.
Divide the roasted potatoes among four bowls.
Top each bowl with taco meat, then cheddar cheese while everything is still warm.
Finish with sour cream, salsa, lettuce, tomatoes, olives, green onion, and jalapeño. Serve immediately.