Preheat the oven to 350°F. Spray a 3-quart casserole dish with nonstick cooking spray.
In a large bowl and with an electric mixer, blend together the Rotel, cream cheese, mayo and sour cream until smooth. Stir in the chicken and cheese and pour into the prepared dish.
Bake 25 to 35 minutes. Serve with tortilla chips for dunking.
Notes
It's okay to use low fat mayonnaise and low fat sour cream in this recipe, but don't try to cut back on the fat for the cheddar cheese. Low fat cheddar cheese doesn't melt very well at all and you won't get the hot and cheesy result that you're looking for in this dip.