Preheat oven at 350°F. Spray 2-8x8-inch square baking dishes with non-stick cooking spray.
Heat quick-cook rice in microwave, per package instructions. Lightly combine cooked rice, the next 6 ingredients and salt and pepper in a large mixing bowl.
Pour 3/4 of rice mixture into baking dishes and spread to create an even level across each dish. Lay sliced avocado, distributing evenly on top in both dishes. Spread remaining rice mixture on top of avocado slices. Sprinkle cheese on top to cover casseroles.
Place dishes in preheated oven for 20 to 25 minutes; until cheese is thoroughly melted and started to turn brown. Remove from oven and let sit for 5 minutes. Serve warm with tortilla chips, corn chips and/or wheat crackers.