Preheat your grill to medium-high heat.
Husk the corn, removing all silk and leaves.
Lightly coat each ear of corn with oil to prevent sticking.
Place the corn on the grill and cook for about 10-12 minutes, turning occasionally until charred.
While corn is grilling, mix mayonnaise, lime juice, and salt in a bowl.
Once grilled, remove corn and let it cool slightly.
Brush each ear generously with the mayonnaise mixture.
Sprinkle crumbled cotija cheese over the corn.
Dust with chili powder for added flavor.
Garnish with fresh cilantro and lime wedges before serving.