In a bowl, combine the sliced chicken thighs, chopped chipotle peppers, minced garlic, onion powder, garlic pepper, paprika, dried oregano, salt, and pepper. Mix well to ensure the chicken is evenly coated. Let it marinate for at least 15 minutes.
Heat grapeseed oil in a skillet over medium-high heat. Add the marinated chicken and cook until browned and crispy on the edges, about 6-8 minutes per side. Ensure the chicken is fully cooked with no pink in the center.
In the same skillet, add thinly sliced onions. Cook over medium heat until they are soft and caramelized, about 5 minutes.
Remove from the cooked chicken and onion mixture skillet and set aside.
In the same skillet, warm the tortillas until they are pliable and have soaked up all the flavor from the skillet. Place a portion of the crispy chipotle chicken on each tortilla.
Sprinkle shredded cheese over the chicken while it's still hot. Allow the cheese to melt slightly.
Add a generous amount of caramelized onions on top of the melted cheese. Finish by spooning pico de Gallo over the tacos.
Fold over the tortillas and cook on each side until crispy and the sticks to the cheese to almost look like a quesadilla.
Serve the Crispy Chipotle Chicken Tacos immediately. Optionally, garnish with additional fresh cilantro, lime wedges, or your favorite hot sauce.