In 3-quart saucepan, heat 2 tablespoons oil over medium-high heat. Add onions and chile; sprinkle with 1/2 teaspoon pepper and 1/4 teaspoon salt. Cook 5 minutes, stirring frequently. Stir in frozen corn, tomatoes and broth. Heat to boiling over high heat, stirring occasionally. Reduce heat to low; cover and simmer 10 to 15 minutes.
Meanwhile, in small food processor bowl, place all pesto ingredients except oil. Cover; process with on-and-off pulses 2 or 3 times to mix. With food processor running, slowly drizzle 2 tablespoons oil into mixture, processing about 30 seconds or until well blended. Set pesto aside.
In blender or with immersion blender, blend chowder (in 2 batches, if necessary) about 30 to 60 seconds or until almost smooth. Stir in half-and-half. Heat just until warm.
Ladle chowder into individual bowls. Top each with 1 heaping tablespoon pesto to be swirled in before eating.