Lightly toast the dried oregano, cumin, and garlic powder in a dry pan for 30 seconds before mixing with sour cream to intensify and bloom their flavors dramatically.

Use rice that's cooked to just al dente rather than fully tender, as it will continue cooking in the casserole's moist environment and prevents mushiness.

Create distinct layers—rice on bottom, seasoned chicken in middle, salsa-sour cream mixture on top—before mixing to ensure even seasoning throughout rather than uneven pockets.

Mix half the scallions into the casserole before baking and sprinkle the remaining half as a fresh garnish after baking to maintain their bright color and crisp texture.

Let the casserole rest covered for 5 minutes after baking so the cheese sets properly and the flavors meld, making it easier to serve without falling apart.