Peel and dice the sweet potatoes. Add them to a large pot and cover with water. Bring the potatoes to a medium boil. Cover and cook the sweet potatoes until they are very soft and, when pierced with a fork, easily slide off (about 20 minutes).
Preheat the oven to 350 F (180 C).
Drain the potatoes and transfer them to a large bowl. Add the orange juice, cinnamon, nutmeg, salt, and ¼ cup of orange juice. Use a potato masher to mash the potatoes, adding more orange juice until smooth.
Transfer the potatoes to a 9x13-inch casserole dish and spread them evenly.
Combine the almond flour, coconut sugar, pecans, and 2 tablespoons of orange zest in a small bowl. Add 2 tablespoons of orange juice and mix well. Spread the topping evenly over the sweet potatoes.
Add the sweet potatoes to the oven and bake for 35 minutes until the topping is brown and the sweet potatoes are hot. If the topping gets too brown, cover it with foil for a few minutes.