Cook the egg noodles in salted water per the package instructions, then drain well. Set aside.
Roughly chop the rotisserie chicken.
Preheat the oven to 350°F. Spray a 13x9-inch baking dish with nonstick cooking spray. Set aside.
In a large bowl stir together the cream of celery soup, cream of chicken soup, milk, sour cream, garlic salt, granulated garlic, lemon pepper, onion powder and black pepper.
To the bowl, add the noodles, chicken, peas and carrots, green onions and 1 cup cheddar cheese. (Reserve some green onions for garnishing.)
Pour the noodle mixture into the the prepared dish. Sprinkle the top with the reserved cheddar cheese.
In a small microwave safe bowl melt the butter. Toss with the cracker crumbs then sprinkle evenly on top.
Place into the oven and bake for 35-45 minutes or until the top is golden brown and the casserole is bubbly.
Serve immediately garnished with green onions.