This traditional Georgian dish was taken by a Japanese fast food place and adapted to be... well, more oily and cheesy. It's a very filling dish, leaving you feeling full of butter and garlic, what else is there to ask for?
This recipe uses some cream stew roux which might not be easy to find in the US (found on Amazon but bit pricy). I think you can just use flour (since there's milk and butter in here as well you can get a beschamel-style texturing going on)
(Recommended music while listening to this is this playlist of Georgian music)
cut up the sweet potato into largish bite-sized chunks. Rinse heavily.
Lightly wrap the sweet potato and microwave (3 minutes at 600W)
cut the chicken into bite-sized chunks
place chicken into a deep-ish frying pan with a teaspoon of oil. Let one side of the chicken simmer on medium heat for 5 minutes (skin side down, you want to get it nice and crispy)
flip the chicken pieces to cook the other side, and mix in 10g or so of shaved garlic
once the garlic smell gets nice and strong, add in 200ml of milk and 15g of butter. Cover with a lid and let cook under low heat for 5 minutes
Cut the heat, and add in the sweet potatoes. Also either add in the 1/4 block of cream stew roux, or some flour (add slowly and mix, this is mainly a texture adjustment)
turn on the low heat and cook (uncovered for 5 more minutes)
at last, squirt in a bit of lemon juice and soy sauce, and throw some shredded cheese and parsley over the whole thing.
Eat with some rice, and feel extremely full afterwards.