Preheat the oven to 400°F (200°C).
Peel and thinly slice the potatoes to about 1/8-inch thick.
Toss the potatoes with olive oil, garlic powder, paprika, salt, and black pepper.
Arrange half of the potatoes in a lightly greased 9×13-inch baking dish.
Heat a large skillet over medium-high heat.
Cook the diced onion for about 4 minutes until softened.
Stir in the garlic and cook for 30 seconds.
Add the ground beef and cook until browned, breaking it into crumbles. Drain excess grease if needed.
Stir in the tomato paste, tomato sauce, chili powder, cumin, smoked paprika, oregano, onion powder, garlic powder, salt, and black pepper.
Cook for about 5 minutes until the mixture thickens.
Spread the taco beef evenly over the potatoes.
Sprinkle with 1 cup of the cheddar cheese.
Layer the remaining potatoes on top.
Cover tightly with foil and bake for 40 minutes.
Remove the foil, sprinkle with the remaining cheddar cheese and Monterey Jack cheese.
Bake uncovered for another 15 to 20 minutes until the potatoes are fork tender and the cheese is golden and bubbling.
Let the casserole rest for 10 minutes.
Garnish with green onions, cilantro, sour cream, diced tomatoes, jalapeños, avocado, or salsa before serving if desired.
