In a small bowl, combine the soy sauce, water, rice wine vinegar, brown sugar, regular sugar, garlic, and ginger.
Whisk well until combined.
Using a ziploc bag, place the chicken thighs into a large Ziploc Bag.
Pour the soy sauce mixture into the Ziploc bag to coat the chicken. Seal the bag and toss it a bit to get the chicken fully coated.
To get it to fully soak in, let it sit for at least 60 minutes or more. These can be prepared in the morning and can sit all day in the fridge to marinate as well if preferred.
Coat the basket of the Ninja Foodi with grapeseed oil spray, then place the chicken thighs evenly into the basket. (This was done in 2 batches with 4 chicken thighs each to fit.)
Cook at 390 degrees for 8-10 minutes, using the Air Crisp function of your Ninja Foodi.
Rotate the chicken carefully.
Cook for an additional 5-8 minutes until they reach an internal temperature of 165 degrees. This took 15 minutes in my Ninja without pre-heating.
Remove and serve with diced green onions.
Notes
Remember that all air fryers heat differently, it's best to use a meat thermometer to get the right timing for the chicken. It's well done when the internal temperature reaches at least 165*F.