Preheat an outdoor grill to 400°F. Brush the corn lightly with melted butter. Place the corn on the grill grates and cook for 8–10 minutes, turning occasionally, until the corn is tender and lightly charred in spots.
For the air fryer: Preheat the air fryer to 400°F. Brush the corn lightly with melted butter. Place the corn on the air fryer basket and cook for 10-15 minutes, turning occasionally, until the corn is tender and lightly charred in spots. (The exact time depends on the wattage of the air fryer.)
For the oven: Preheat the oven to 400°F. Brush the corn lightly with melted butter. Place the corn directly on the middle oven rack or on a baking sheet. Roast for 25 to 30 minutes, turning once, until the kernels are tender. For an authentic grilled char, raise oven temp to "Broil" for the last 3 to 5 minutes.
While the corn cooks, stir together the mayonnaise, sour cream, lime zest, lime juice, chili powder, garlic powder, and salt in a small bowl until smooth.
When the corn is finished cooking, brush or spoon the creamy mixture over each ear while it is still hot.
Roll in Cotija cheese and sprinkle with chopped cilantro, then dust lightly with additional chili powder. Serve immediately with lime wedges for squeezing over the top.