Heat the oil in a large skillet over medium-high heat. When it’s hot and shimmering, add the onion and cook to soften until translucent, 2-3 minutes. Stir in the garlic and freshly grated ginger and cook for another minute, until fragrant.
Turn the heat down to medium-low and add the red curry paste, curry powder, coriander, and cumin and stir to combine. Continue to cook, stirring frequently, for 2-3 more minutes, until very fragrant.
Add 2 cups of the diced mango and the can of full-fat coconut milk. Stir to combine the milk with the spices and seasonings. Turn the heat up to high and bring to a boil then turn it down to low and simmer for 8-10 minutes.
While it’s simmering, dice the chicken and season it well with salt and pepper.
When the sauce is done simmering, carefully transfer it to a large food processor or high-speed blender. Start blending on low speed and slowly turn it up to high speed. Blend until completely smooth, 2-3 minutes, stopping to scrape down the sides as needed. It may take longer if your blender isn’t as strong.
Pour the mango sauce back into the pan and bring it to a strong simmer over medium-high heat. Turn the heat down to medium-low and add the cubed chicken. Stir to coat then cover and cook for 8-10 minutes (Note 1 chicken thighs), or until the internal temperature reaches 165°F.
Stir in the remaining cup of diced mango, finely chopped cilantro, and lime juice. Taste and add more salt as needed. Serve with rice