Preheat your oven to 350°F and lightly grease a 9x13 inch baking dish or similar size. While the oven heats, remove the cream cheese from the refrigerator to soften to room temperature—this ensures it'll blend smoothly without lumps. Shred the chicken into bite-sized pieces and set aside. Grate the cheddar cheese from the block (about 1.5 cups total) and measure out the mozzarella, as freshly grated cheese melts far more smoothly than pre-shredded varieties. Thinly slice the green onions on a bias and crumble the blue cheese, keeping them separate for layering.

In a large mixing bowl, combine the softened cream cheese, buffalo sauce, sour cream, and garlic powder. Stir vigorously until smooth and fully incorporated—there should be no cream cheese lumps. Add the shredded chicken and gently fold it in until evenly distributed throughout the mixture. Now fold in half of the grated cheddar and half of the mozzarella (about 1/2 cup each), along with most of the sliced green onions, reserving some for garnish. I like to taste at this point and adjust the buffalo sauce if needed—some prefer it spicier, others more mild.

Transfer the creamy dip mixture from Step 2 into your preheated baking dish, spreading it into an even layer. Top with the remaining cheddar and mozzarella (about 1/2 cup each), distributing it evenly across the surface for consistent melting. Sprinkle the crumbled blue cheese over the cheese layer—the tanginess will cut through the richness beautifully. Reserve the remaining fresh green onions for garnish after baking.

Place the assembled dip in the preheated 350°F oven and bake for 15-20 minutes, until the cheese is melted and the edges are bubbling—you're looking for golden spots on top and a gentle bubble around the perimeter. I prefer to bake it until it's lightly golden rather than pale, as this develops more flavor in the cheese. Oven temperatures vary, so check around the 15-minute mark to avoid over-browning.

Remove the baking dish from the oven and let it rest for 2-3 minutes before serving. This brief rest allows the dip to set slightly and makes it easier to scoop without it being too loose. Garnish with the reserved fresh green onions for a pop of color and freshness. Serve warm with your choice of keto-friendly dippers like celery, cheese crackers, or pork rinds.