Preheat the oven to 350 degrees F (175 degrees C). Grease an 8x8-inch baking dish.

Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels. Season chicken with salt and pepper.

Bring a large pot of lightly salted water to a boil. Add chicken breasts, reduce heat, and simmer until no longer pink in the centers and juices run clear, about 15 minutes.

While chicken cooks, steam cauliflower rice in its package in the microwave on high power for 5 minutes. Let cool slightly.

Combine milk and ranch dressing mix in a mixing bowl. Mix in cooked cauliflower rice. Mix in 1/2 cup Mexican cheese and cream cheese.

Chop bacon and chicken; add to the mixing bowl with green onions and combine. Pour contents into the prepared dish. Sprinkle remaining Mexican cheese on top.

Bake in the preheated oven until cheese is melted and bubbly, about 30 minutes.