Whisk peanut butter, soy sauce, vinegar, honey, and garlic in a small bowl until smooth. Gradually add vegetable oil, whisking constantly until emulsified; set aside.
Cook noodles in a large saucepan of boiling salted water according to package instructions until al dente. Drain; rinse under cold water, then drain again.
Toss noodles, chicken, celery, bean sprouts, and daikon in a large bowl with three-quarters of reserved dressing to combine and evenly coat; season with salt. Top with sesame seeds and drizzle remaining dressing and chili oil over.
Do Ahead: Dressing can be made 1 day ahead. Cover and chill.
