Heat 2 tablespoons of olive oil in a skillet over medium heat. Add diced chicken breasts and cook for about 6-8 minutes until golden brown. Set aside.

In the same skillet, pour in the jar of butter chicken sauce and return the cooked chicken. Stir well and simmer on low for about 5 minutes. Add 1/4 cup of heavy cream if desired.

Slice one onion thinly. In a separate pan, heat another tablespoon of olive oil. Add onion, 1 tablespoon of brown sugar, and Worcestershire sauce. Cook for 10-15 minutes until dark brown.

Preheat the oven to 400°F (200°C). Prepare a baking sheet with parchment paper or oil.

Place frozen naan on the baking sheet. Spread the butter chicken mixture over each naan and top with caramelized onions and grated mozzarella cheese.

Bake for approximately 10 minutes until cheese is melted and naan edges are golden brown.

Remove from oven, cool for a minute, and garnish with cilantro and yogurt. Serve hot.