In a bowl, combine the first 5 ingredients; set aside. In a large nonstick skillet or wok, stir-fry garlic in oil for 30 seconds. Add mixed vegetables and red pepper; stir-fry until crisp-tender, 4-5 minutes.
Remove and keep warm. Add half of the cod to skillet; gently stir-fry until fish flakes easily with a fork, 3-5 minutes. Remove and keep warm. Repeat with the remaining cod.
Stir broth mixture and add to the pan. Bring to a boil; cook and stir for 2 minutes or until thickened. Return vegetables and fish to the pan. Add peanuts. Gently stir to coat. Cover and cook until heated through, about 1 minute. Serve over rice.