Preheat oven to 350°F (175°C).
Press biscuit dough evenly into the bottom of a greased 9x13-inch baking dish.
Bake biscuit layer for 10 minutes until lightly golden.
Brown ground beef and onion in a skillet and drain excess fat.
Stir in taco seasoning and water and simmer for 3–4 minutes.
Spread seasoned beef evenly over baked biscuit base.
In a bowl, mix sour cream, mayonnaise, garlic powder, and black pepper.
Spread creamy mixture over beef layer.
Top with sliced tomatoes and bell peppers.
Sprinkle cheddar and Monterey Jack cheese on top.
Bake for 25 minutes until cheese is melted and bubbly.
Let rest 5–10 minutes before serving.