Chicken and Corn Soup with Chile-Mint Salsa

Char chiles over a gas flame or under a broiler, turning occasionally, until blackened all over (this adds a smoky flavor and makes the skins easy to remove). Let cool. Using a small knife, scrape skin from chiles; discard. Coarsely chop chiles (for a milder salsa, discard seeds).
Make a paste by mincing garlic and 1 teaspoon salt on a work surface, scraping with the side of knife occasionally. Add chiles and finely chop, then add mint and finely chop. Transfer to a bowl; stir in oil. Season with more salt, if desired. DO AHEAD: Salsa can be made 1 day ahead. Cover; chill. Return to room temperature before using.
Place chicken and broth in a large heavy pot. Add water just to cover chicken. Bring to a simmer over high heat, skimming the surface occasionally (foam can add bitter flavors to soup; discard it as you skim). Reduce heat to medium-low; simmer, continuing to skim surface occasionally, for 5 minutes. Add corn cobs, halved onion, garlic, carrot, celery, peppercorns, bay leaves, and 2 teaspoons salt. Reduce heat to low and simmer until breast meat is just cooked through, 15-20 minutes.
Transfer chicken to a cutting board; let cool slightly. Cut off breast meat; set aside (cooking breast meat longer will make it tough). Return chicken to pot. Simmer over low heat until legs and thighs are cooked through, about 20 minutes longer.
Remove pot from heat. Transfer chicken to a platter; let cool slightly. Strain broth through a fine-mesh sieve into another large pot; discard solids. Shred all chicken meat, discarding skin and bones.
Bring strained broth to a simmer. Add corn kernels and cook until heated through, about 3 minutes. Add red onion; cook until crisp-tender, about 5 minutes. Add chicken; simmer, stirring occasionally, until heated through, about 5 minutes. Season with salt.
Divide soup among warm bowls. Garnish with tomato and tortilla chips. Squeeze lime wedges over; add wedges to soup. Serve, passing chile-mint salsa and sea salt alongside.