1. Preheat your grill to medium-high heat. Brush the grill grates with olive oil to prevent sticking.
2. Season the chicken breasts with salt and pepper. Grill the chicken for about 6-7 minutes on each side, or until fully cooked and juices run clear. Once done, let it rest for a few minutes before slicing it into thin strips.
3. While the chicken is grilling, brush the pizza crust with olive oil on both sides. Place it on the grill for about 2-3 minutes on each side, or until slightly charred and crispy.
4. Remove the crust from the grill and spread a generous layer of barbecue sauce over it. Arrange the sliced chicken evenly over the sauce.
5. Sprinkle the mozzarella and cheddar cheese over the chicken, followed by the red onion slices.
6. Place the pizza back on the grill, close the lid, and cook for another 5-7 minutes, or until the cheese is melted and bubbly.
7. Remove the pizza from the grill and garnish with fresh cilantro. Slice and serve immediately.

One tip I learned from my mother is to always let the chicken rest before slicing. This allows the juices to redistribute, making the chicken tender and juicy—just like she did with her famous grilled tacos.