Heat a drizzle of olive oil in a large skillet over medium-high heat. Add the frozen grilled corn in a single layer and cook, stirring occasionally, for 5–7 minutes until the corn is warmed through and you see some additional char and color developing. You want some golden, toasted spots — don't stir too much so the corn gets some contact with the pan.
Remove from heat and let the corn cool for about 10 minutes — you want it warm but not steaming hot when you dress it.
Transfer the corn to a large bowl. Add the mayonnaise, crema, chili powder, lime juice, red onion, and half the cotija. Toss to combine.
Fold in the fresh cilantro. Taste and adjust salt, pepper, and lime juice as needed.
Transfer to a serving bowl. Top with the remaining cotija, a dusting of chili powder, and extra cilantro. Serve at room temperature with lime wedges on the side.