Grease Instant Pot with cooking spray. Set aside.
Whisk together broth, 1/4 cup orange juice, vinegar, soy sauce, honey, garlic, orange zest, red pepper flakes, ground ginger, and black pepper.
Pour half into Instant Pot.
Place in chicken breasts.
Pour remaining sauce over chicken breasts.
Cover and lock lid (ensure steam releasing handle is pointing to “sealing").
Cook using the manual button (set to high pressure) and adjust timer on the Instant Pot to 12 minutes.*
The Instant Pot will beep when it's finished.
Flip the valve to "venting" for a quick release.
Remove chicken and set aside.
In a small bowl, whisk together cornstarch with 2-4 tablespoons of orange juice.***
Whisk that mixture into the Instant Pot.
Press the saute button on the Instant Pot and bring the sauce to a simmer.
Add chicken back in and simmer until the sauce has thickened, about 5 minutes.
Shred the chicken directly in the pot as the sauce is thickening.
Taste and re-season, if necessary and serve!