Begin by cooking the chicken and shredding it if not already. If you are making this in the Ninja Foodi, add the boneless chicken breast or thighs to the wire rack inside the pot of the Ninja Foodi along with 1 cup of water. Cook in high pressure for 10 minutes, quickly release the pressure, and shred the chicken. Let the chicken rest in the fridge for about 30 minutes to chill.
Combine the cooked chicken, green onions, yogurt, mayo, rosemary, dill weed, mustard, salt, and pepper in a large bowl. Squeeze the juice of 1/2 a lemon into the mixture as well. Mix up well and coat the chicken.
Chill in the fridge for 30 minutes or more until ready to serve.