Spray a grill or cast iron skillet with nonstick cooking spray and heat to medium-high heat. Add the corn on the cob to the grill or skillet and char each side for 2-3 minutes or until corn begins to brown and char.
Once all sides are lightly charred and kernels are bright yellow, remove from heat and place on a plate to cool; set aside.
In a small bowl, combine yogurt, mayonnaise, lime juice, chili powder and salt. Use a basting brush and spread on all sides of the corn then coat each piece of corn in cotija cheese.
Sprinkle chopped cilantro on top of corn and serve.