Combine the chili powder, kosher salt, and sugar in a small bowl. Rub the spice mix over the corn.
Heat a grill pan over medium heat. Coat the grill pan with cooking spray. Add the corn to the pan and cook for 10 minutes, or until completely cooked through. Turn the corn occasionally to ensure it cooks evenly.
Remove the corn from the pan. Top the corn with lime zest and butter. Serve immediately with lime wedges. Squeeze some lime juice over the corn before eating.