Heat oven to 375 degrees. Lightly mist a 13- by 9-inch baking dish with non-stick spray and set aside.
In a microwave-safe container with a lid, micro cook greens for 8 minutes, stirring at the halfway point. Remove and drain greens in colander to remove any excess water, if any. When cool enough to handle, gather greens into a mass on a cutting board and chop a few times with a large knife, to make smaller pieces.
Meanwhile, heat oil or butter in a skillet and sauté the onion until it begins to brown slightly, about 5-7 minutes.
In a large mixing bowl, mix cooked onion, cooked greens, cooked rice, sour cream, cottage cheese, salt, pepper, green chiles and 2/3 of the shredded cheese. Mix well, and pour into prepared baking dish. Top with remaining 1/3 of shredded cheese.
Bake, uncovered, for 30 minutes, or until bubbly and hot. Garnish with a sprinkle of chopped cilantro or parsley if you like.
Note: This is a great way to use up leftover rice, and makes a nice, comforting vegetarian main dish. Serve with a fresh green salad and steamed broccoli on the side for a healthy non-meat lunch or dinner.