Clean potatoes, cut them in half, place in TC steam rack, add 2 C water. Cover, high heat, valve open for 20 minutes, DO NOT over cook! Do not let the pan go dry.
While that is cooking, finely mince the garlic and onion.
Remove the potatoes from the TC and set aside to cool, pour off the water. Place the chicken in the base of the TC, add 3-4 T of water, cover, valve open, high heat for 3 minutes, turn the chicken over, add another 3-4 T of water, cover, valve open, high heat for another 3 minutes. The chicken should be done by now, it it's not, just follow the last step one more time. Remove the chicken, chop the chicken into small pieces. Add the onions to the TC, add 3-4 T water, cover, valve closed, medium high heat for 3 minutes, add the garlic, add more water if it looks dry (3-4 T), cover, valve closed, medium high heat for 2 more minutes, if there is a lot of liquid left over, cook it down until it's almost dry, remove from the TC and set aside.
Using a spoon or a melon baller,scoop out each potato half, being careful to leave just enough to support the skin. Place the potato halves back in the steam rack, it's easier if you put the steamer rack in the TC now. Put the part you scooped into a bowl, add the onion/garlic mixture, cheese, sour cream, egg, salt and pepper (to taste). Mash/mix until mostly smooth, then add the chicken, stir until equally incorporated.
Put some of the mixture in each potato half, try to use all of the mixture, each one will be mounded up pretty tall. Sprinkle the tops with paprika. Add 1 1/2 C water to the base, cover, valve open, high heat for 15 minutes.