Add the chicken breast to a bowl and season with salt, chili powder, garlic powder, and cumin.
In a large skillet, heat 2 tablespoons vegetable oil and cook chicken until slightly charred and no longer pink. Cook chicken in batches to avoid overcrowding the pan. Remove cooked chicken from the skillet, and transfer into a bowl.
Heat another tablespoon of oil, add the onions and cook for a couple minutes until onions are slightly translucent.
Add the garlic and peppers and cook slightly, then remove from heat. Transfer garlic and peppers to the chicken bowl, then top with lime juice.
Lay down half the tortilla chips on the skillet, followed by half the fajita mixture, and top with pepper Jack and cheddar cheese. Repeat with the remaining ingredients.
Bake until the cheese has melted, about 15 minutes.