While tortillas are cooking, in a medium pot, heat remaining 1 tablespoon olive oil and cook onion over medium-high for 3 minutes. Add corn and 2 cups broth. Bring to a boil, reduce heat, and cook for 2–3 minutes, until corn is just done. Using a food processor or immersion blender, purée about half of the soup, in batches, until smooth. Add up to 1/2 cup of remaining broth to achieve desired consistency. Stir in bell pepper and cook over medium-high heat for 2–3 minutes, until just crisp-tender.