Cook onion in oil in a large pot over medium-high heat until soft, 5-6 minutes.
Stir in peanut butter and curry powder, cook 1 minute, then add tomato purée, water and salt.
Bring to a boil and add chicken. Reduce heat to a simmer and cook until the chicken is very tender, about 40 minutes.
Meanwhile stir together Chobani and cilantro.
Serve chicken in bowls topped with the Chobani-cilantro mixture and peanuts.