Heat the olive oil in a large saucepan over medium-high heat. Add the rice and stir to coat with the oil. Add the coconut milk, orange juice, water, and salt and bring to a boil. Cover and reduce the heat to low. Simmer until all the liquid is absorbed, about 20 minutes.
Remove the rice from the heat and fluff with a fork. Place a clean, dry dish towel over the pan, cover with a lid, and let the rice steam for 5 minutes. Stir in the butter and cashews.
Cut off the top and bottom of the orange, just exposing the flesh. With a sharp knife, follow the curve of the fruit to cut away the peel, completely removing the white pith. Slice out each segment of orange, cutting along the membranes. Cut each segment into thirds. Stir the orange into the rice. Serve hot.