Vidalia onion dip

i saw this a couple years ago on the food network and tried it. It is so yummy. And so easy to make

3 cups chopped Vidalia onions
3 cups shredded Swiss cheese
2 1/2 cups mayonnaise
Garlic salt, to taste

Mix all ingredients and pour into greased 1 1/2 quart baking dish. Bake in a preheated 350 degree oven for 35 to 40 minutes until lightly brown. Serve with corn chips.