In a large skillet, heat the olive oil over medium-high heat. Add the poblano, onion and chili powder and cook, stirring, until fragrant, about 4 minutes. Add the beef and cook, breaking up the meat, until the meat is just cooked through, about 3 minutes. Stir in the tomato and tortilla chips and season with salt and pepper.
Divide the meat mixture among 4 plates and top with the cheese.