Bring a large pot of water to a boil. Add the husked corn and boil for 6–8 minutes, until the kernels are tender.
While the corn boils, melt the butter in a small saucepan over medium-low heat. Whisk in the chili powder, smoked paprika, garlic powder, cayenne, and salt. Cook for 60 seconds, stirring constantly. Remove from heat and whisk in the lime zest and juice.
Drain the boiled corn and pat dry. Heat a grill, grill pan, or broiler to high and char the corn for 3–4 minutes, turning every minute, until blackened spots form.
Brush each ear of corn generously with the warm chili-lime butter, coating all sides.
Sprinkle with crumbled cotija cheese and chopped cilantro. Serve immediately with extra lime wedges.