Step 1

Whisk broth, soy sauce, ginger, and pepper flakes together in large bowl. Pat chicken dry with paper towels. Using metal skewer, poke skin side of chicken 10 to 15 times. Add to bowl with broth mixture and toss to coat; set aside to marinate for 10 minutes.

Step 2

Remove chicken from marinade and pat dry with paper towels. Measure out 2 tablespoons remaining marinade and combine with sugar, mirin, and cornstarch in bowl; discard remainder. Microwave, stirring occasionally, until thickened and bubbling, about 1 minute; set aside.

Step 3

Arrange chicken skin side up in air-fryer basket, spaced evenly apart. Place basket in air fryer and set temperature to 400 degrees. Cook until chicken is golden, crisp, and registers 195 degrees, 20 to 25 minutes, rotating chicken halfway through cooking (do not flip). Brush chicken skin with thickened marinade mixture. Return basket to air fryer and cook until chicken is well browned, about 5 minutes. Transfer chicken to serving platter, tent with aluminum foil, and let rest for 5 minutes. Measure out ½ teaspoon fat from air-fryer drawer; discard remainder.

Step 4

While chicken rests, toss reserved fat, snow peas, garlic, lemon zest, salt, and pepper together in bowl and transfer to now-empty basket. Place basket in air fryer and cook until snow peas are crisp-tender, 2 to 3 minutes. Transfer to serving bowl and toss with lemon juice. Serve with chicken.