Heat the olive oil in a large pot over medium heat. Add the diced onion and poblano peppers and cook for 5 minutes until they soften.
Stir in the minced garlic and cook for 1 minute. Add the tomato paste, cocoa powder, cumin, and cinnamon and stir for another minute to coat the vegetables.
Pour in the vegetable broth and add the rinsed lentils. Bring the mixture to a boil, then lower the heat and simmer uncovered for 25 minutes, stirring occasionally.
Add the sweet corn kernels, salt, and black pepper. Continue simmering for 10 more minutes until the lentils are tender.
Ladle the stew into bowls and top with chopped cilantro. Serve with lime wedges on the side.