1. Preheat the oven to 450°. In a blender or food processor, puree the tomatillos, garlic, jalapeño and cilantro until smooth. In a large saucepan, heat the oil until shimmering. Add the cumin and coriander and cook over high heat until fragrant, 30 seconds. Add the tomatillo puree, bring to a boil and cook until the sauce loses its bright green color, 3 minutes. Season with salt and pepper.
2. In a medium bowl, toss the chicken with 3/4 cup of the pepper Jack, the farmer cheese, scallion and half of the tomatillo sauce; season with salt and pepper. In another bowl, toss the tortilla chips with the remaining sauce.
3. Spread half of the chips in an 8-by-11-inch baking dish; top with the chicken and cover with the remaining tortilla chips. Don't pack the chips down. Dollop the sour cream over the chips and sprinkle with the remaining 3/4 cup of pepper Jack. Bake for 15 minutes, or until the cheese is browned. Serve at once.