Preheat the oven. Set to 350°F (175°C). Grease a 9x13-inch baking dish.
Mix the creamy base. In a large bowl, whisk the cream cheese, sour cream, mayonnaise, and condensed soup until smooth. If the cream cheese is firm, let it sit at room temp or microwave it in short bursts to soften.
Season it right. Stir in garlic powder, onion powder, salt, pepper, and lemon juice.
Taste and adjust seasoning. If you like a looser sauce, add the chicken broth a little at a time.
Add the chicken and cheese. Fold in the shredded chicken and cheddar until evenly coated.
Assemble the casserole. Spread the mixture in the baking dish, smoothing the top. Sprinkle with parsley if using.
Make the crunchy topping. Combine crushed crackers with melted butter.
Scatter evenly over the casserole for a golden, buttery crust.
Bake. Cook uncovered for 25–30 minutes, until the edges bubble and the topping is lightly browned.
Rest before serving. Let it sit for 5–10 minutes to set slightly. This makes cleaner scoops and better texture.