Place 1 diced mango in a food processor or blender and puree until smooth. Set aside.
Heat 1 tablespoon vegetable oil in a large skillet or Dutch oven over medium-high heat. Add chicken to pan and season well with salt and pepper. Sauté over medium-high heat until chicken is no longer pink.
Transfer chicken to a medium bowl and heat remaining oil in same pan. Add onion and zucchini to pan, season with salt and pepper, and sauté until crisp-tender.
Add garlic, ginger, curry powder, coriander, and cumin to vegetables and cook 1-2 minutes until fragrant. Add pureed mango, diced mango, cooked chicken, diced tomatoes, and coconut milk to pan and bring to a simmer.
Reduce heat to medium-low and allow curry to simmer 15-20 minutes to allow the flavors to meld, stirring occasionally.
Season curry with salt and pepper to taste and serve warm over rice with cilantro and naan. Enjoy!