How to Make It
Light a grill. Arrange four 14-inch sheets of heavy-duty foil on a work surface.
In a large bowl, toss the chicken, onion and all the peppers with the olive oil and cumin seeds. Season generously with salt and pepper and toss again. Pile the chicken and vegetables evenly on one half of each foil sheet and top with the oregano and lime. Fold the foil over the ingredients and pinch the edges to seal.
Place the foil packets on the grill, close the lid and cook over moderately high heat until the chicken is cooked through, about 12 minutes. Open the packets and serve with warm flour tortillas, sour cream and hot sauce.