Preheat the oven to 400°F (200°C).
In a mixing bowl, toss the halved Brussels sprouts with olive oil, chili powder, cumin, garlic powder, salt, and pepper until well coated.
Spread the Brussels sprouts in a single layer on a baking sheet. Roast in the preheated oven for 20 minutes, stirring halfway through, until they are golden brown and tender.
In the last 5 minutes of cooking, add the corn kernels to the baking sheet with the Brussels sprouts and allow them to roast together.
In a separate bowl, mix the mayonnaise, lime juice, and half of the cotija cheese.
Once roasted, remove the Brussels sprouts and corn from the oven. Drizzle the mayonnaise mixture over the hot vegetables and toss to combine.
Garnish with the remaining cotija cheese and fresh cilantro before serving.