Sweet potato and black bean enchiladas

Name: Sweet potato and black bean enchiladas
Cuisine: Mexican, Latin American, American, TexMex
Ingredients: 300g sweet potato; 1 tbsp olive oil; 1 red onion; 2 cloves garlic; 1 bell pepper; 1 tin black beans; 2 handfuls spinach; 625ml enchilada sauce; 1 TSP chili powder; 0.5 TSP ground cumin; 5 tortillas; 25g fresh coriander; 1 medium avocado; 1 lime; 0.5 TSP garlic powder