Position a rack in the top shelf of the oven and preheat to broil. Arrange the corn chips on a large, heatproof platter in a single layer to overlap slightly. Sprinkle the cheese over the chips, then dot evenly with the salsa.
Cut grilled corn off the cob; sprinkle over the nachos.
Broil until the cheese is bubbling, 3 minutes. Remove the platter from the oven, dollop with the creme fraiche and top with roasted poblano strips and ancho chile powder.
