Heat olive oil in a 10-inch, non-stick skillet over medium-high heat. Add chicken cubes and cook until chicken is lightly browned and cooked through, about 5-7 minutes. Add butter chicken sauce. Mix well and reduce heat to medium-low. Cook and stir until mixture is hot and bubbly. Remove from heat and let mixture cool slightly. Sauce will thicken as it cools.
Spread saucy chicken evenly over naan bread. (If you like your pizza saucier, add more sauce!) Sprinkle half the cheese of the chicken, followed by pineapple, onions and bell peppers.
Top with remaining cheese.
Carefully slide pizzas directly onto middle oven rack. Bake for about 10 minutes, until crust is lightly browned and cheese is melted. Remove pizzas from oven, sprinkle with cilantro, if using, and serve hot.