Preheat oven to 350 degrees F. Butter a 9x13 (or similar) casserole dish.
Cook rice using chicken broth instead of water (use package directions). Remove from heat and fold in the chiles and sour cream (reserve a little bit of sour cream for the top).
Layer half of the rice mixture and half of each cheese. Sprinkle with onion salt. Layer the rest of the rice on top. Sprinkle with more onion salt. Spread the reserved sour cream on top. Then sprinkle the rest of the cheese on top.
Cover and bake for 30 minutes.
*If you are preparing this recipe as GLUTEN-FREE, just be sure to use brands of chicken broth and chiles that are known to be GF.