These snack bites will satisfy your game-time munchies. You might want to make a double batch just in case!
Preheat the oven to 400°. Rub the potatoes with 1 tbsp. oil and place on a foil-lined baking sheet. Bake until tender, about 1 hour. Let cool.
Meanwhile, in a medium skillet, heat the remaining 2 tbsp. oil over medium. Add the chorizo. Cook, stirring often, until browned, 2 to 5 minutes. Add the onion and chile. Cook, stirring often, until soft, 5 to 8 minutes. Sprinkle with the flour. Cook, stirring often, until the flour turns golden, 1 to 2 minutes. Add the milk. Cook, stirring often, until the sauce is smooth and thickened, about 1 minute. Reduce heat to low. Add the cheese blend. Cook, stirring gently, until the cheese sauce is smooth; season with salt and pepper.
Preheat the broiler. Halve each potato lengthwise. Scoop out the flesh, leaving a 1/4-inch border inside the skin. (Reserve the flesh for another use.) Place the potato skins cut-side up on the foil-lined baking sheet. Divide the cheese sauce among the potatoes; top with the red onion. Broil until the sauce is bubbling and the edges of the potato skins are crisp, 3 to 4 minutes. Transfer the potato skins to a platter. Top with the Cotija, scallions, and hot sauce.