In a large bowl, whisk together orange juice, lemon juice, soy sauce, sesame oil, serrano pepper, lemongrass or lemon zest, and ginger.
Fill a large skillet 3/4 full with water, add a sprinkle of salt and bring to a simmer. Add chicken tenders and cook 5 to 7 minutes or until chicken is tender. Drain chicken and shred directly into bowl with dressing.
Bring a large pot of salted water to a boil. Add soba and shiitakes; cook 3 minutes. Add bok choy and broccoli; cook 1 to 2 minutes or until noodles are al dente.
Drain noodles and vegetables and add to bowl with chicken and dressing. Toss gently to combine. Garnish with basil if desired.