In a microwave-safe bowl, combine glutinous rice flour, mango nectar, sugar, and oil. Stir and mix well.
Cover with plastic wrap and microwave for 3 1/2 minutes in 1-minute intervals, followed by the last 30 seconds. Be sure to mix the mochi in between each interval so it cooks evenly throughout.
While the mochi is cooling down, cut the mango into square pieces, about 1 1/2 inches thick. The pieces should fit in the middle of the mochi so you don't want them to be too big otherwise, it'll be challenging to form.
Dust potato starch on a clean work surface area or cutting board. Transfer the mochi onto the cutting board and sprinkle potato starch on top. Coat the rolling pin with potato starch as well.
Carefully roll the mochi out to 1/4 inch thickness. Using a 3-inch ring mold or lid, cut the mochi out into 4 pieces.
Place one piece of mango in the center of the mochi and fold the sides towards the center. Be sure to crimp the mochi so it sticks together. Repeat for the rest of the mochi.
Once the mochi is formed and shaped to your liking, brush the mochi with mango nectar. This will help the coconut flakes stick to the mochi. Toss the coated mochi into the coconut flakes and enjoy!