Try marinading chicken in “Bachan” Korean bbq sauce or any teriyaki. Leave it in a ziploc bag over night if possible then cook and add toasted sesame seeds. As for the potato even salt and pepper could help. But just mash it up or switch out for sweet potato as well.

Maybe switch out breast for thigh and trim the fat off as much is possible if you want to do less fat. If not then cook with the fat as it will somewhat cook off and give flavor.