Preheat grill to high heat or preheat grill pan to high.
Make blackened spice butter. Combine melted butter with paprika, cumin, cayenne, salt, pepper, garlic powder, and onion powder until well combined. Set aside.
Lay corn on the grill and cook, turning often until charred all over, about 10 minutes. Remove corn from the grill and brush butter evenly on all sides.
Place corn on serving platter and sprinkle about 2 tablespoons parmesan per corn. Sprinkle chopped chives and serve with lime wedges.
Notes
If preparing the corn ahead of time, keep warm in the oven at 200 degrees F, covered, until ready to serve.