In a bowl, stir mayo with yogurt, lime juice, garlic, salt and cayenne. Grease grill and preheat barbecue to medium-high.
Drain peaches well and chop. Place in a bowl along with slaw, coriander and mayo mixture. Stir.
Sprinkle both sides of chicken with TexMex seasoning and a pinch of salt if there isn’t any in the seasoning mix. Set on barbecue and grill turning halfway through until cooked, 4 to 6 minutes in total. Thinly slice.
To assemble, warm shells or tortillas. Toss chicken with slaw and serve with hot sauce if using.