Preheat oven to 400°F. Line a rimmed baking sheet with parchment paper. Spread tater tots in an even layer onto prepared baking sheet. Bake until golden-brown and crisp, about 10 to 15 minutes.
Remove from oven and top evenly with 1 cup of cheese, tomato, onion, barbecue sauce and chicken. Sprinkle with remaining cheese, and bake until golden-brown and cheese is melted, about an additional 10 to 15 minutes.
Drizzle with barbecue sauce. Garnish with green onions, and serve.
