Preheat the oven to 375º. In a medium to large bowl, whisk together the eggs and coconut milk. Add the neufchatel cheese and whisk until roughly combined. Set aside.
In a skillet, warm up the olive oil over medium heat. Add the minced garlic. Once the garlic is golden brown, add all the onions. Stir, and add the salt, cayenne pepper, and black pepper. Let sweat for about 5-6 minutes, add the bell peppers, and cook for another 5-6 minutes.
Add the potatoes and chard stems and cook for another 10 minutes more. Lastly, add the chard leaves. Cover skillet with a lid, and let cook for 5-6 mins more. Once the veggies are cooked through, transfer to a bowl and set aside.
Grease a shallow casserole dish on all sides with some olive oil, and set aside. You can also use a medium to large cast iron skillet. Pour the egg mixture into the bowl with the veggies. Using a spatula or wooden spoon, stir the ingredients together. Add the chopped sage, and stir once or twice more.
Pour into the vessel of choice, and place the frittata in the oven for about 20-35 minutes. When the center had puffed and there is a golden brown color to the top of the frittata, its ready. Cool before serving.