Prepare the beef sirloin pieces by cutting them uniformly.
In a mixing bowl, combine soy sauce, honey, rice vinegar, garlic, ginger, and sesame oil.
Add the beef to the mixing bowl and coat well with the teriyaki sauce.
Pour the marinated beef along with the sauce into the Ninja Foodi pot.
Seal the Ninja Foodi and set it to pressure cook for 15 minutes.
After cooking, perform a quick release of the pressure.
In a small bowl, mix cornstarch with a tablespoon of water to create a slurry.
Add the slurry to the pot and select the sauté function to thicken the sauce.
Once thickened, garnish with chopped green onions before serving.
