Heat oil in Wok. Meanwhile, cut chicken into strips. Add chicken and stir-fry for 2–3 min, until golden. Remove and set on a plate.
Chop broccoli; slice bell pepper. Add broccoli, pepper, and seasoning to wok. Drizzle with a little water; cover and steam for 2 min, until tender-crisp. Meanwhile, stir broth with cornstarch.
Return chicken to wok and pour broth mixture on top. Simmer, uncovered, for 1 min, until sauce is thick.