Preheat the oven to 375°F. Lightly spray an 8x8-inch baking dish with cooking spray.
Slice the dinner rolls in half, if they are pull apart rolls you can leave them stuck together and slice them all at the same time. Place the bottom halves into the prepared baking dish.
Spread the pesto sauce over the bottom halves of the dinner rolls. Spread the chopped chicken on top of the pesto, and sprinkle the mozzarella cheese over the chicken. Cover with the top halves of the dinner rolls.
In a small bowl, whisk together the butter, garlic salt and parsley. Brush this mixture over top of the sliders and cover the whole dish tightly with aluminum foil. Bake for 15-20 minutes, or until the cheese is melted. Serve warm.
For the rolls, I used these dinner rolls. If you use that recipe, make the rolls a bit smaller then called for, using 2 ounces of dough per roll, which will give you 18 rolls total. The baking time is the same, and the baked rolls freeze beautifully. If you bake them in 8x8-inch baking dishes instead of on a sheet pan (make sure to grease the dishes!) then they will be ready to proceed with this slider recipe, and will fit in the dish perfectly. Alternatively, you can use store-bought tray buns for this recipe.