Preheat the oven to 350ºF. Grease a 9×13″ baking dish or two small casserole dishes.
Preheat a large skillet and add butter to melt. Add chopped celery and diced onion. Sauté the onions & celery until translucent and then add garlic.
Add chopped chicken and let heat through for about 3 minutes.
Stir in 3/4 cup buffalo sauce, simmer for a few minutes and remove from heat.
In a large bowl, mix quinoa, cream of chicken soup, mayo, 1/4 cup buffalo sauce, and 1 cup cheese together until well combined.
Gently fold in the chicken/celery/onion mixture. Divide mixture between baking pans or pour into a large 9x13 casserole dish. Top with 1/2 cup cheese. Bake for 35-45 minutes, until the top is golden and the casserole is bubbling.
Serve with bleu cheese dressing and celery sticks!