Vegetarian Lentil Tacos (Slow Cooker)

• 1 1/2 cups green lentils, picked over and rinsed
• 3 cups vegetable broth
• 1 (10 oz) can mild diced tomatoes and green chiles
• 1 Tbsp olive oil
• 1/2 cup finely chopped yellow onion
• 2 tsp minced garlic 
• 2 tsp ground cumin
• 1 1/2 tsp chili powder
• 1 1/2 tsp ancho chili powder
• 1 tsp paprika
• Salt and freshly ground black pepper, to taste
• 3 Tbsp chopped fresh cilantro
• 1 Tbsp fresh lime juice

For serving

• Corn tortillas or crisp taco shells, lettuce, cheese, tomatoes (for serving)