Preheat the oven to 375°F (190°C) and spray a 4-quart baking dish with nonstick spray.
Pat the chicken breasts dry with paper towels and arrange them in a single layer in the prepared baking dish; season lightly with additional salt and pepper if desired.
In a large bowl, beat the cream cheese until smooth, then add garlic powder, onion powder, cumin, 1/2 teaspoon salt, ground black pepper, the diced green chiles (with their juices), and the green enchilada sauce; mix until fully combined and smooth.
Spread the cream cheese and green chile mixture evenly over each chicken breast, then sprinkle the shredded Colby Jack cheese over the top.
Bake uncovered for 30–35 minutes, until the chicken reaches 165°F (74°C) in the thickest part and the cheese is melted and bubbly.
Let the dish rest for 5–10 minutes before serving.
