Grilled Chicken Quesadillas

Preheat a grill pan over medium heat and oil the grates. Season chicken breast with chili powder, cumin, oregano, ½ teaspoon salt and pepper, and grill, turning occasionally, until browned and cooked through, 5 minutes per side. Remove chicken to a cutting board and let cool until vegetables are cooked. Meanwhile, in a medium bowl, toss the onion and bell pepper with 1 teaspoon oil and season with salt and pepper. Grill the vegetables, turning occasionally, until lightly charred in places and just tender, about 8 to 10 minutes total. Remove vegetables from grill to a cutting board.  Slice the chicken into thin strips and roughly chop the peppers and onion.