Preheat oven to 350°F and grease a 9x13-inch baking dish.
Press biscuit dough into the bottom of the prepared baking dish, stretching to cover the entire bottom and slightly up the sides.
In a large skillet over medium-high heat, brown the ground beef with diced onion until fully cooked, then drain excess fat and stir in taco seasoning according to package directions.
Spread the seasoned beef mixture evenly over the biscuit dough layer.
In a medium bowl, combine sour cream, mayonnaise, 1 cup of shredded cheese, and green chiles, then spread this mixture over the beef layer.
Top with remaining 1 cup of cheese, diced tomatoes, and sliced black olives.
Bake for 35-40 minutes until the biscuit crust is golden brown and the cheese is melted and bubbly.
Let stand for 5 minutes before cutting into squares and serving.