Gently mix chicken, oats, egg, salt, and pepper; refrigerate 15 minutes, included in prep time. With damp hands, shape 24 equal meatballs.
Heat 1 tablespoon oil in deep 12-inch skillet over medium. Brown meatballs in 2 batches 3 minutes per side, adding remaining oil for second batch. Plate partly cooked.
Add peas and measured water; cover and steam 2 to 3 minutes until bright green and crisp-tender. Transfer to separate bowl.
Lower heat; stir in garlic 30 seconds. Add honey, soy sauce, lemon juice, pepper flakes, and broth; gently simmer.
Return meatballs and juices; partly cover. Simmer 6 to 8 minutes, turning once, until largest centers 165°F.
Mix cornstarch and cold slurry water; stir into simmering sauce 1 minute until glossy. Return peas; warm 1 minute. Serve 6 meatballs with one-quarter peas and sauce per portion.