Preheat the oven to 375°F (190°C). Lightly spray a 9x13-inch casserole dish with nonstick cooking spray.

In a medium bowl, combine the Red Lobster Cheddar Bay Biscuit Mix (including seasoning packet) with ¾ cup cold water. Stir until just combined. Spread the dough evenly across the bottom of the prepared casserole dish. If the dough is too sticky, lightly spray your hands with cooking spray and spread it out.

Bake the biscuit dough for 5-8 minutes, just until the dough is set. Remove from the oven and set aside.

In a large skillet over medium heat, cook the ground beef with diced onion, breaking up the meat as it cooks. Once browned, drain any excess grease.

Stir in the taco seasoning, ¼ cup water, drained fire-roasted diced tomatoes, and undrained diced green chilies. Let the mixture simmer for 2-3 minutes, stirring occasionally.

Spread the beef mixture evenly over the partially baked biscuit dough in the casserole dish.

In a small bowl, mix together mayonnaise, sour cream, and 1 cup of shredded Colby Jack cheese. Spread this mixture evenly over the beef layer.

Sprinkle the remaining 1 cup shredded Colby Jack cheese over the top of the casserole.

Bake the casserole for 30 minutes, or until the top is melted and bubbly. Remove from the oven and let it cool for 5 minutes.