Preheat your oven to 425°F (220°C).
In a large bowl, toss the halved Brussels sprouts with olive oil, garlic powder, chili powder, smoked paprika, salt, and pepper until evenly coated.
Spread the Brussels sprouts in a single layer on a baking sheet. Roast in the preheated oven for 20-25 minutes, or until they are golden brown and crispy, stirring halfway through.
While the Brussels sprouts are roasting, heat a small skillet over medium heat. Add the corn and cook for about 5-7 minutes, stirring occasionally, until heated through and slightly charred.
In a small bowl, mix together the mayonnaise, lime juice, and cayenne pepper (if using).
Once the Brussels sprouts are done, remove them from the oven and toss them with the charred corn. Drizzle the mayonnaise mixture over the top and sprinkle with cotija cheese and chopped cilantro.
Serve immediately while warm.