Heat grill to high. Place cheese on a plate or in a shallow bowl; set aside.
Brush corn with butter, and season with salt and pepper. Grill, turning every 2 to 3 minutes, until tender and slightly charred, 10 to 12 minutes; let cool 2 to 3 minutes.
Brush corn with mayonnaise, and roll in cheese to coat. Sprinkle with chili powder; serve with lime wedges.