In a large 12-inch nonstick skillet over medium heat, add the ground meat, salt, pepper, and onion. Cook, breaking the meat into small pieces, until the meat is cooked through. Drain any excess grease.
Add the chili powder, cumin, coriander, tomato sauce and jalapeño (if using). Cook over medium heat for 2-3 minutes, stirring often. Stir in the water, spinach and beans and simmer for 4-5 minutes. Remove from the heat.
Lightly grease the center of 6-8 foil pieces, each about 12-inches long.
Place about 1 cup of sweet potato chunks in the center of each piece of foil arranging them into somewhat of a single layer; sprinkle with salt and pepper (don't skip this step!). Add a heaping 1/2 cup or so of the meat mixture on top. Bring the long sides of foil together over the filling and fold tightly down. Fold and crimp each edge until tightly sealed and a little packet is formed. Repeat with all the pieces of foil and ingredients.
Place the foil packets in a single layer on a large, rimmed baking sheet and bake for 20-25 minutes until the potatoes are tender.
Carefully open the foil packets and serve with taco toppings and garnishes of your choice.
Nutrition Facts:the nutrition facts for this recipe were calculated based on the packet ingredients (but do not include the garnishes as those are added based on personal preference).