Place husked tomatillos and jalapeños in a medium saucepan, cover with water, and boil for 10-12 minutes until tomatillos turn olive green and are soft. Drain and cool for 5 minutes.
Transfer cooled tomatillos, jalapeños, garlic, half the onion, crema, cilantro, salt, cumin, and broth to a blender. Blend on high for 45-60 seconds until smooth. Adjust seasoning to taste.
Heat oil in a sauté pan over medium heat. Cook finely diced onion for 3-4 minutes until softened. Add minced garlic and cook for 30 seconds until fragrant. Stir in shredded chicken, season with salt and cumin, and warm through for 1-2 minutes. Set aside.
Preheat oven to 375°F (190°C). Spread about one-third of the tomatillo sauce (3/4 to 1 cup) evenly over the bottom of a 9x13-inch baking dish.
Heat 1/2 inch of vegetable oil in a small skillet over medium-high heat. Fry each tortilla for 10-15 seconds per side until pliable and slightly golden. Drain on paper towels and keep warm under a clean kitchen towel.
Lay a fried tortilla flat, spoon 2-3 tablespoons of chicken filling down the center, add a pinch of Oaxaca cheese, roll tightly, and place seam-side down in the baking dish. Repeat with remaining tortillas and filling.
Pour remaining tomatillo sauce evenly over the rolled enchiladas, ensuring complete coverage. Sprinkle with remaining Oaxaca cheese. Bake uncovered for 18-22 minutes until cheese is melted, bubbly, and lightly golden.
Rest for 3-5 minutes before serving. Garnish with queso fresco, fresh cilantro, sliced white onion, and pickled jalapeños. Serve immediately while hot.