Preheat oven to 350 degrees.In a large skillet, cook bacon. Chop cooked bacon into pieces.In a large bowl, toss together tater tots, cooked bacon, and cheeses. Pour into a lightly greased 9x13-inch pan.Whisk together eggs, Ranch mix and milk. Pour over tater tot mixture.Cover and refrigerate at this point if baking later.Bake for 40 - 50 minutes, or until eggs are set.