Cut the celery into 1/2" pieces. Slice the Carrots into 1/2" slices. Dice the onion into 1/2" dice
Turn the NInja Foodi on high sear/saute. Add butter, onions, celery, and carrots. Saute for 2 minutes.
Add 3 cups of cut up chicken. Saute for 1-2 minutes and add in chicken bone broth
Add in cream of celery soup and do not stir. Put the pressure lid on and turn the valve to seal. Pressure cook on high for 2 minutes. When the time is up, immediately release the pressure and turn the Ninja Foodi to sear/saute on medium.
Sift the flour into a large mixing bowl. Add salt and baking powder. Stir to combine
Cut in the small pieces of butter with a pastry cutter until the flour mixture resembles course crumbles.
Remove the thyme leaves from the stem and add into the flour mixture.
Make a well in the center of the flour and add sour cream and half and half. Stir just until the liquid combines with the flour mixture and forms a loose dough. If it is dry and really crumbly, add 1 tsp of half and half at a time until it comes together and is no longer crumbly.
Dump the dough onto a clean work surface and fold the dough until all loose crumbs are incorporated, you don't want to knead it.
Fold the dough towards you and turn 90° and fold again towards you. Do this until the dough is combined. Roll into a log.
Break off dime size pieces and add to rapidly simmering broth. Simmer for 10-15 minutes or until the dumplings are cooked through. Take one out and give it a taste, if it tastes floury or doughy, let simmer another few minutes.