Preheat the oven to 350 degrees F.
In a medium bowl, toss together the oats, Chex cereal, the 2 tablespoons melted butter and 1/8 teaspoon of the salt. Spread the mixture onto a baking sheet and bake until deep golden brown and fragrant, about 10 minutes, stirring halfway through the baking time.
In a medium bowl, whisk together the flour, coffee, baking soda and remaining 3/4 teaspoon salt. In a large bowl, using a wooden spoon, mix together the 10 tablespoons room-temperature butter, granulated sugar and brown sugar until creamy. Stir in the egg and vanilla. Then carefully fold in the chocolate, peanuts, sour cherries, potato chips and the oat and Chex mixture. Scoop the dough into 2-tablespoon scoops and roll each one into a neat ball. Freeze the dough balls for at least 1 hour.
Preheat the oven to 325 degrees F.
Set the dough balls at least 3 inches apart on parchment-lined baking sheets and sprinkle with the flaky sea salt. Bake until the cookies are golden brown and the centers are just set, 18 to 22 minutes, rotating the sheets halfway through. Let the cookies cool on the baking sheets for 10 minutes, then transfer to a rack to cool completely.