Preheat oven to 350F. If you have extra time and want the chicken to be very tender, add it to a large bowl and heavily salt it. Let that sit at room temperature to "dry brine" while you're preparing the rest of the ingredients. This is not as necessary if you're using chicken thighs.
In a food processor, add the cottage cheese, buffalo sauce, garlic cloves, dill, parsley, onion powder, celery salt, salt, pepper and cayenne, if using. Blend until smooth, scraping down the sides as needed.
Then, bring a large pan to medium high heat. Once hot, add enough oil to coat the bottom of the pan. Then, add cubed chicken, celery and carrots. Season with some salt & pepper. Let that cook, undisturbed for about 3 minutes, then stir and continue cooking for another 3 minutes or until chicken is browned. It's okay if it's not fully cooked as it'll finish cooking in the oven.
Thaw out the cauliflower rice in a bowl in the microwave or on the stovetop — you don’t need it to be hot, just warm! Then, use a thin dish towel or paper towel and squeeze out all the liquid from the cauliflower rice — don’t skip this step! Otherwise, your casserole will be too liquidy.
Add the blended buffalo cottage cheese, cooked chicken, celery & carrots, green onion, and the cauliflower rice to a 8×12 or 9×13” baking dish. Use a spatula to mix it up. Spread out evenly in the pan.
Cover with foil and bake for 20 minutes. Then, add shredded cheese and return to the oven & cook, uncovered for 10 more minutes - SEE NOTE**. At the end, switch the oven to broil for 2-4 more minutes.
Top with an extra drizzle of buffalo sauce & ranch as well as some chopped green onion or parsley. Enjoy!