Grilled BBQ Chicken Pizza with Jalapeño Ranch Sauce

In a blender, combine the sour cream, yogurt, mayonnaise, lime juice, cilantro, dill, chives, jalapeno, and garlic and blend until smooth.
Season to taste with salt and pepper.
Refrigerate until ready to use, up to 2 days ahead.

Prepare a charcoal grill with high- and low-heat zones. Clean and oil the grates well.
Season the chicken breasts with salt and pepper and place directly on the grill grates over high heat. Grill until the bottom is browned and releases easily from the grates, 1 to 2 minutes.
Flip the chicken over and brush the tops lightly with barbecue sauce.
Move the chicken to the low heat side of the grill and continue cooking, flipping the chicken over a few times and brushing with about half of the barbecue sauce, until the chicken is well charred, glazy, and just cooked through, 15 to 20 minutes total.
Transfer to a cutting board and let rest for at least 5 minutes, then cut into ½-inch pieces.

Lightly brush a HexClad Pizza Steel with oil.
On a lightly floured work surface, stretch or roll the dough into a 36cm round.
Transfer to the center of the Pizza Steel (do not preheat Pizza Steel) and reshape into a 36cm round if necessary.
Spread about 240ml of the barbecue sauce over the crust, leaving a 1.5cm border. Scatter the cheese over, followed by the diced chicken and onion.
Scatter the coals all over the bottom of the grill and replace the grate. Place the Pizza Steel on the center of the grill, close the cover, and bake until the crust is golden brown and the cheese is melted, about 10 to 15 minutes. (Alternatively, bake the pizza on the center rack of a 260° oven for about 10 minutes.)