
Preheat grill to medium-high. Brush grill grates with oil.
Rub corn and jalapeños with olive oil; season with salt and pepper. Grill corn and jalapeños, uncovered, until kernels start to brown and soften, about 10 minutes.
Cut kernels off cobs (you should have about 3 cups); transfer to a bowl. Dice jalapeños, remove seeds if desired; add to bowl with corn. Stir in cheese, mayonnaise, Greek yogurt, scallions, lime juice, chili powder, and granulated garlic.
Serve dip with tortilla chips.