Heat coconut oil in a large skillet or wok over medium-high heat.
Add the chicken pieces and sear until golden brown on all sides, approximately 5-6 minutes; remove chicken and set aside.
In the same skillet, sauté the diced onion until translucent, about 4 minutes.
Add the minced garlic, grated ginger, and red curry paste; cook for 1-2 minutes until highly fragrant.
Pour in the coconut milk and mango puree, whisking to incorporate the curry paste.
Return the chicken to the skillet and add the fish sauce and brown sugar.
Reduce heat to medium-low and simmer for 10-12 minutes until the sauce has thickened and chicken is cooked through.
Fold in the diced mango and lime juice, cooking for an additional 2 minutes to warm through.
Garnish with fresh cilantro and serve over jasmine rice.