Heat frying pan with olive oil until hot. Add onion and cook for 3-4 minutes until soft.
Add the corn and cook for a further 5-6 minutes, leave the corn still in the pan to char slightly. Remove from the heat and cool for 5 minutes.
Stir in the cilantro, mayonnaise, sour cream, chipotle hot sauce, salt & pepper and juice from half the lime.
Decant into serving bowl or plate and sprinkle with cotija cheese. Add a few pinches of chilli powder and then finally squeeze over the remaining half of lime just before serving. Serve warm or at room temperature.