Preheat a grill. Combine the lime zest, chipotle powder, garlic, paprika, salt and sugar in a bowl and stir with a fork until combined. Mash in the butter until thoroughly mixed in with the spices.
Peel back (but don't remove) the husks from the corn and remove the silks. Brush the corn generously with the butter and fold the husks back over the corn. Grill over medium heat, turning occasionally, until the corn is cooked through and bright yellow, 12 to 15 minutes.
This butter can also be used as a wet rub on grilled meats with a dab at the end of cooking, just before serving.