Char the corn: Grill over medium-high heat (about 400F) for 10-12 minutes, turning every couple of minutes, until tender with charred spots on all sides. (No grill? Broil 4-5 inches from the element for 8-10 minutes, turning often, or sear in a dry cast-iron skillet over medium-high heat for 8-10 minutes.)
While the corn cooks, stir together the mayonnaise, Mexican crema, lime juice, lime zest, chili powder, garlic powder, and salt in a small bowl.
Transfer the hot corn to a platter (insert wooden skewers into the base of each ear if desired). Brush the sauce generously over each ear, coating all sides while the corn is still hot.
Spread the crumbled cotija on a plate and roll each sauced ear through it, pressing gently so the cheese sticks. Sprinkle with chopped cilantro.
Dust with an extra pinch of chili powder and serve immediately with lime wedges for squeezing.