Preheat oven to 425°F. Spread frozen tater tots evenly on a baking sheet and bake for 25–30 minutes until golden and crispy, flipping halfway through. Warm tortillas in a dry skillet for about 20 seconds per side until soft and flexible. In a small bowl, mix sour cream with taco seasoning. Lay one tortilla flat and spread 1–2 tablespoons of seasoned sour cream down the center. Add a handful of crispy tater tots. Sprinkle about 1/3 cup shredded cheddar over the tots and drizzle with a small amount of nacho cheese sauce if using. Add optional cooked ground beef or black beans and spoon salsa on top. Fold sides inward and roll tightly into a burrito. Heat vegetable oil in a skillet over medium heat and place burrito seam-side down. Cook for 2–3 minutes until golden, then flip and cook another 2–3 minutes. Repeat with remaining burritos and serve immediately.