Start by boiling the chicken breasts. Bring a large pot of water to a boil, then add the chicken. Once it returns to a boil, turn off the heat and cover the pot. Let the chicken poach for 25 minutes. This keeps it juicy and tender. After poaching, let it rest to cool slightly before shredding with forks or fingers.
While your chicken is cooking or cooling, preheat your oven to 350°F. Lightly spray a 9x9-inch baking dish with non-stick spray. This helps prevent sticking and makes cleanup easier. If you don’t have a 9x9 dish, any similar-sized casserole dish will work fine.
In a medium saucepot over medium-low heat, combine the cubed cream cheese, ranch dressing, hot sauce, black pepper, and garlic powder. Whisk constantly to ensure the cream cheese melts smoothly into the hot sauce and ranch. This step is crucial to make a velvety base for your dip.
Once the sauce is smooth, stir in the shredded chicken, green onions, 1 cup of mozzarella, and 1 cup of cheddar. Mix well so everything is coated in the sauce. The chicken will soak up the flavor, and the cheese will start melting in. This step builds all the layers of creamy, spicy, cheesy goodness.
Transfer the mixture into your greased baking dish and top it with the remaining shredded mozzarella and cheddar cheeses. Bake in the preheated oven for 20–30 minutes, or until the cheese is fully melted and bubbly at the edges. Then switch to BROIL mode for 2–3 minutes to get a golden brown, crispy top.
Once out of the oven, serve it hot with tortilla chips, veggie sticks, crackers, or even warm bread. It also makes a great filling for wraps or sandwiches if you have leftovers. This dip tastes best fresh but reheats well in the microwave or oven.