Slice chicken in half lengthwise to create ½-inch-thick cutlets, then season with a few pinches of salt. Rest for 5 minutes. Transfer the chicken to a small mixing bowl and add the Chipotle Marinade. Stir to coat, then cover and rest at room temperature for at least 20 minutes or refrigerate for up to 24 hours.

Preheat the oven to 375ºF.

Heat 1 tablespoon of neutral oil in a large oven-safe skillet over high heat. Once the oil is hot and shimmering, use tongs to transfer the chicken from the marinade, letting excess drip off, to the skillet. Sear for 2 to 3 minutes, until browned and lightly charred in spots, then flip. Transfer the skillet to the oven and bake until cooked through and the internal temperature reaches 165ºF, about 6 minutes. Transfer the chicken to a cutting board and dice into bite-sized pieces; set aside.

Meanwhile, heat the remaining tablespoon of neutral oil in a large non-stick pan over medium heat. Once the oil is hot, add the onion and cook until soft and lightly seared, about 5 minutes. Transfer the onion to a bowl and set aside.

In the now-empty pan over medium-low heat, sprinkle 2 to 3 tablespoons of Oaxaca cheese in small mounds (working in batches if necessary). Once melted, gently place a tortilla over each mound. Cook until the cheese is golden brown and crispy, 1 to 2 minutes. Flip, then fill one side of each tortilla with ¼ cup of diced chicken and about 1 tablespoon of sautéed onion. Fold each tortilla in half and apply light pressure using a spatula. Cook each side until golden brown and crispy, about 2 minutes.

Transfer the tacos to a plate and garnish with cotija and Pickled Jalapeños & Shallots. Serve with cabbage, radishes, and Roasted Jalapeño Vinaigrette.