Heat the oil over medium-high heat in a large pot. Add the onion, jalapeño, and ½ teaspoon salt. Cook, stirring occasionally, until the vegetables soften, about 5 minutes. Add the garlic, cumin, and ½ teaspoon pepper. Cook, stirring for 30 seconds. Add the vegetable broth and tomatoes (along with their juices) and bring to a boil. Reduce heat and simmer for 10 minutes, breaking up the tomatoes with a potato masher or back of a spoon.
Add the tortilla chips and lime juice and simmer for another 2-3 minutes or until the chips are very soft.
Working in batches, blend the soup until smooth. Taste and add more salt and pepper, if desired.
Serve with chopped cilantro, sour cream, lime wedges, and more chips, if desired.