Prepare the Tater Tots:
Preheat your oven to 425°F (220°C) and spread the tater tots in a single layer on a baking sheet. Bake according to the package instructions until crispy and golden brown, about 25-30 minutes, flipping them halfway through for even cooking.

Cook the Ground Beef:
While the tater tots are baking, cook the ground beef in a skillet over medium heat. Break it up into small pieces and cook until browned and fully cooked, about 6-8 minutes. Drain any excess fat, then stir in the taco seasoning and 1/2 cup of water. Simmer for 2-3 minutes until the beef is fully coated and the seasoning is absorbed. Remove from heat.

Assemble the Tachos:
Once the tater tots are cooked, spread them out on a large serving platter or baking sheet. Sprinkle the cooked ground beef evenly over the tater tots. Then, top with shredded cheddar cheese and mozzarella (if using).

Melt the Cheese:
Place the platter or baking sheet with the tater tots and toppings back into the oven for about 5-7 minutes, or until the cheese is melted and bubbly.

Top the Tachos:
Once the cheese is melted, remove the platter from the oven. Top with diced tomatoes, red onion, jalapeños, black olives (if using), and sliced green onions. Add a dollop of sour cream, guacamole, and salsa on top, if desired.

Garnish and Serve:
Garnish the tacos with fresh cilantro and serve immediately while the cheese is gooey and the tater tots are still warm!