Heat the olive oil in a large nonstick skillet over medium heat. Add the baby bell peppers in a single layer and cook, turning, until the skins blister and start browning, about 8 minutes. Transfer to a plate.
Add the onion, poblano, garlic, cumin, oregano, ancho and chipotle chile powders and 1 teaspoon salt to the skillet. Cook, stirring, until the onion and poblano are tender, about 8 minutes. Increase the heat to medium high and add the pork. Cook, breaking up the meat with a wooden spoon, until no longer pink, about 6 minutes. Remove from the heat; let cool.
Meanwhile, preheat the oven to 425 degrees F. Make a slit in each baby bell pepper with a paring knife, cutting from stem to tip. Crumble the meat mixture into small bits, then stir in the cilantro and cheese. Stuff 2 to 3 teaspoons of the meat mixture into each pepper using your fingers or a small spoon; transfer to a baking sheet. (The peppers can be stuffed up to 4 hours ahead; cover and refrigerate. Bring to room temperature before baking.)
Bake until the peppers are hot and the cheese melts, about 10 minutes. Season with salt and serve with lime wedges.