If using an oven, place rack in the upper third of the oven and preheat to a high broil. If using a grill, preheat to medium high.
Place corn on sheet pan and drizzle with oil, salt, and black pepper. Rub to coat evenly. If using the oven, place the sheet pan under the broiler until the corn is charred on all sides, 2-3 minutes per side, depending on the strength of your broiler. If using a grill, cook on all sides until lightly charred, 2-3 minutes per side.
While the corn cooks, make the dressing: Using a tall glass (mason jar) and an immersion blender or in the bowl of a food processor or blender, combine mayonnaise, sour cream, chipotles in adobo, lime zest, and juice. Blend until smooth and creamy. Season to taste with salt and pepper. Add more chipotles for more heat, if desired. Set aside.
Let the corn cool slightly before cutting away kernels from the cob. Use a large shallow bowl to help catch any runaway kernels, hold the cob upright in the middle of the bowl and use a sharp knife to slice off the kernels. Rotate and continue to cut off the kernels of all the corn.
In a large bowl, mix corn kernels, scallions, cilantro, and half of the cheese. Toss with a few Tbsps of dressing (you will have leftover). Season with salt, pepper, and a squeeze of lime, if needed.
Serve in a shallow bowl or platter and top with remaining cheese, extra cilantro, a drizzle of olive oil, and sprinkle of Tajin (if using). Serve immediately. Leftovers will keep in an airtight container for up to 3 days.
Leftover chipotle crema is great on tacos, as a dip for nachos! Or just more corn salad, because just one batch is never enough! :)